Archive of Our Own

Chapter Text

Part One: Endorphins

Shishio Tsukasa does not believe in fairytales.

There is no magic that will take dull things and make them beautiful. There is no true love that will break through the dark and conquer all. Most importantly, there are no knights in shining armour, no heroes that will save those in need.

It is something that becomes all too clear when one is set loose into the world with nothing. It lights a scathing fire that burns low in Tsukasa’s stomach on a daily basis, pressuring him to be more ruthless and take what is necessary for his survival. If he were truly on his own, he is not sure how he would manage without drowning under the weight of it all.

But instead, there is Mirai.

By his own design, Mirai is not like him. She was shoved into Tsukasa’s arms moments after her birth, when he was only five years old himself. He cradled her clumsily, holding her thin blanket close to his chest as chaos ensued in the emergency room his mother had been rushed into.

They were shoved out to the hall, and Tsukasa was forced to stand on his tiptoes to see through the glass into the room. It’s a distant memory now, but he recalls the flurry of white and blue as the doctors scrambled to resuscitate his mother; and he remembers his heart in his throat, the tears cascading down his face, and his world quaking like it was crumbling when the scrambling finally stopped. A cloth was placed over his mother’s pale face, the doctors stepped away in defeat, and his father was somewhere far away as her time of death was announced.

His mother had told him of Mirai’s chosen name weeks before this. Tsukasa’s hand was pressed to her belly after she had informed him that his little sister was kicking, urging him to feel.

“I’ve decided on Mirai,” she told him, voice low so as not to disturb Tsukasa’s father, who was slumped over the kitchen table with a bottle of whiskey.

“Mirai?” he repeated.

“It means ‘future’,” she said, one of her hands coming to comb gently through Tsukasa’s hair. “I believe that by giving her a name like that, her life will be a happy one. She’ll always be looking forward to a brighter tomorrow.”

“But what if tomorrow’s bad again?” Tsukasa asked.

“As long as you stay strong and keep going, there will always be some good that awaits you,” she assured him.

Tsukasa nodded, and while he didn’t quite understand it then, the words come back to him later, when he is thrust into the role of Mirai’s caretaker. He alone has to play with her, ensure she gets enough to eat, rock her as she cries, and hold her tiny hands. It’s exhausting and bleak, but when she gurgles out laughter, a wobbly smile stretching across her cheeks, Tsukasa finds himself smiling back, and is certain he would do anything for her.

So, he guides Mirai into believing all the things he himself has no faith in. While there may not be any heroes coming to save him, he could still transform himself into one for her sake.

He reads books and studies stories, relaying them to her and watching as they light up her face. He always chooses those with happy endings, and if they do not already have one, he takes the liberty of providing one himself. He cooks meals for her, purchasing cheap ingredients from money he earns from odd jobs or finds on the sidewalk, and occasionally, the small bills his dad shoves at him after he insists they need more in their empty kitchen. He takes her out of the confines of their home, walking her to the park and pushing her high on the swings. Anything she asks of him, he tries desperately to provide.

Even as those things lead to him becoming less like the knight he’d wanted to be for her.

Mirai’s stomach rumbles as Tsukasa walks her through streets lined with shops, her lips curling into a little pout. Her steps come to a slow halt, and she tightens her grip on Tsukasa’s hand as they linger in front of a bakery’s wide windows. The sweet smell of fresh pastries wafts through the air, strong enough that Tsukasa’s mouth waters.

“It smells so good,” Mirai says, turning to Tsukasa with puppy-dog eyes. “Can’t we get just one?”

Tsukasa swallows back the lump in his throat. “Not today, Mirai.”

He tugs her hand to pull her away, promising her he’d buy her one soon and telling silly stories until she cheers up.

The next day, Tsukasa steals for the first time. A storm roars within him as he races back home, forcing his legs to move faster than they’ve ever taken him. He is panting when he gets back, ushering a confused Mirai to their shared bedroom where he unveils the wrapped-up treat in his hands. Any conflicted feelings he’d possessed are eradicated when Mirai takes the flaky, golden cinnamon roll into her hands, digging into the icing. She chews it quickly, humming delightedly with each bite. She licks at her lips and her eyes twinkle like it’s the most delicious thing she’s ever tasted. Maybe it is.

She thanks him profusely for the treat, her arms winding around his waist as she squeezes him into a hug. It’s the start of a change in him, and he can’t afford to look back.

Tsukasa doesn’t feel like a hero, because even now, heroes don’t exist. Any nobility he has exists for Mirai and Mirai alone.

At least, that’s what he’d assumed.

On the day everything changes, Tsukasa is taking the long walk home from school, forgoing a journey through the city to cross the grassy banks near the riverside. The air of the park is fresh with the mild wind of late summer, and the path before him quiet even with groups of people passing by now and then. He knows he should be getting home soon—while their father tends to ignore Mirai whether he is present or not, she gets bored by herself since she does not possess much for entertainment. 

But out here, he can breathe, and it’s nice, even if it will only last for mere moments.

He stares up at the clouds as he walks. The day is overcast, the sun just barely creeping out from the darkness. It lulls him into a sense of security as he identifies shapes above him.

“You’re such a weirdo!” someone shouts, yanking Tsukasa from his head. “My dad says if you keep doing creepy stuff, you’ll hurt people!”

Tsukasa lowers his gaze, seeking the source of the noise. Three boys are standing below the hill by the river. Their arms are crossed as they glare at another boy, who is kneeling beside a strange mechanical device on the grass and raising a skeptical eyebrow at them. The boy’s hair is unique, a white that fades into green as it trails further up into wild spikes. A stray lock falls into his face, dangling near sharp red eyes. He’s small and unlikely to win if this confrontation escalates, but he doesn’t appear to be afraid.

Tsukasa stops in his tracks, drawn to the scene.

“Huh? Are you dumb? It’s not gonna hurt people,” the boy says dryly. “Not unless I want it to.”

“Stop lying!” one of the others shouts. “My grandma said you blew something up last week!”

The boy nods. “Sure. That happens. Scientific experimentation is all about trial and error. It doesn’t always work out how I want it to in the first few tries.” He raises an arm, showing off the bandage wrapped around it. “I sometimes get hurt, but if you’re scared of the risks, all you have to do is keep your distance.”

Scientific experimentation?

Tsukasa squints, trying to make out the details of the device the boy is fiddling with. He can’t identify what it’s supposed to be. Curiosity grips him, and he finds himself taking a few steps down the stone steps leading to the river.

“Why should we trust you?” one of the bullies sneers.

“Yeah!” says another.  “You’re a weirdo! And no one wants to see all this junk out here, Ishigami!”

He extends his leg, delivering a hard kick against the metal. A hollow bang rings and the device begins to slump on its side. The boy—Ishigami—jumps to his feet, horror overtaking his expression.

“Hey!” he snaps. “Stop it!”

“You want me to stop?” the bully asks, grinning cruelly. He exchanges a look with the others, and invigorated by Ishigami’s distress, the three team up to kick at the device. It must not be made of very sturdy material because it quickly topples over, parts falling off.

Tsukasa’s fingers curl into tight fists, his jaw clenching.

It’s not fair. It’s cruelty at its finest, and it causes the deadly fire coiling deep within him to explode into an inferno.

He sprints down the rest of the stairs on autopilot, catapulting with a shout toward the confrontation. He launches himself at the first of three bullies, knocking him down with a flying kick. The other two, not expecting a fight, turn to him with wide eyes. When one rushes at him, he dodges, then shoves him back hard.

Tsukasa shifts, standing between Ishigami and the attackers. He extends an arm out, blocking their path forward. The glare he directs at them is stone cold.

“What’re you doing?!” the bully he shoved shouts. “Stay out of this!”

The one he’d knocked to the ground gets back up, eyes watering as he clutches at his side. The third stares between his two companions, unsure.

“No. Leave him alone,” Tsukasa orders.

The bully steps forward. “You—!”

“You can fight me if you want, but you’ll lose,” he sneers. “So, back off.”

These boys are not like him. They probably come from the nice houses in the surrounding neighborhoods, where they are safe, secure, and fed. They don’t know what it’s like to be cornered on their walk home. To be forced to learn a rough version of self-defense to keep what little food and money they possess.

Tsukasa is used to fighting, and to his surprise, he’s always been good at it.

The boys exchange a look, and the most hesitant of them steps away, tugging on the sleeves of the others. In a rush, they start to move, muttering curses at him as they retreat.

Tsukasa watches as they go, remaining tense as they disappear into the distance—sneak attacks aren’t unheard of, after all. Only when he has to squint to see their outlines does he finally drop his arm, sighing. He turns around, coming face to face with Ishigami, who is watching him with an unreadable expression.

“Are you okay?” Tsukasa asks.

“I guess,” Ishigami mumbles. He half-heartedly wipes a hand down the white lab coat he is wearing. “Why’d you help me?”

Tsukasa hesitates, considering it.

Because people shouldn’t pick on those who are weaker than them.

Because maybe, he has grown so used to his role of protector that it’s expanded beyond his reach.

“Because… I wanted to,” he answers simply.

Ishigami stares at him analytically, like he’s trying to unravel a mystery, and Tsukasa stares back, not flinching under his scrutiny.

Finally, Ishigami hums, turning away from him and sinking to his knees to examine his wrecked experiment. “Well, they still did a lot of damage. It’s gonna take a while for me to repair it.”

Tsukasa crouches down beside him. He examines the clunky hunks of metal and the few wires coming from it. There are cylindrical parts, and the front of it is more open, like it’s meant to expel something. 

“What is it?” he asks. “An engine?”

Ishigami turns to look at him, a newfound sparkle in his eyes. “It’s a gas turbine engine.”

“So… it powers something? With heat or electricity?” Tsukasa asks. He tilts his head, like seeing it from another angle might make the mechanics easier to comprehend. “How does it work?”

Ishigami flashes him a wicked grin, then begins pointing to various parts of the device as he explains. “Basically, air comes in at this end here and gets compressed in this section. The compression will make it really hot and add a ton of pressure. Then, using this combustor, you add in natural gas for fuel, which when combined with the air will get these blades here to spin. This will release a ton of exhaust out the other end, and if it’s connected to other pieces of machinery, we could use the mechanical energy to generate power.”

“Right,” Tsukasa says slowly, processing that information. “I guess I can see that.”

Ishigami picks up a part that has fallen off completely and frowns. “This is just a lame homemade version though, so this isn’t what they usually look like. It’s only my second time attempt building one, and I’m still learning how to get better at crafting this sort of thing.”

While it definitely looks strange, Tsukasa finds himself staring in amazement nonetheless. 

“You made this all by yourself?” he asks.

“Uh-huh.”

“And do you think it would have worked?”

Ishigami’s expression is downright devious. “It will work. Once I fix it up and resolve any final issues, there’s a ten billion percent chance I’ll get it up and running! Then, I’ll be one step closer to going to space!”

Tsukasa gapes. “Space? How are you going to do that?”

“I’m building a rocket,” Ishigami explains. “Right now, I’m practicing the construction of all the individual components. This engine won’t be used in my actual rocket, it’s too big, but it’ll give me a better understanding of the mechanics. After this, I’m gonna make a rotodynamic pump, and these two things together will make a turbopump, one of the major parts of a rocket’s propulsion system.”

While the actual terminology isn’t clicking for Tsukasa, the enthusiasm and knowledge that Ishigami possesses leaves him breathless.

“And you’re… planning on flying to space by yourself?”

Ishigami sighs. “Not exactly. That sort of thing is too risky to test alone. I’ll have to wait to actually go there myself. The rocket I make will be pretty small but—"

“But you’ll still launch it,” Tsukasa interrupts. “You’ll make something that will go all the way up there.”

Ishigami pauses, watching Tsukasa carefully. “Yeah. I’ll do it no matter what.”

A strange sensation bubbles up in Tsukasa’s chest and runs through his entire body like electricity. His lips curl into a smile, and he can’t help leaning closer.

“I want to see it,” Tsukasa says. “When you get there, will you show me?”

For reasons he does not understand, Ishigami’s ambitions draw him in. The idea of achieving something that grand, to go so far above the earth… it grips Tsukasa’s heart and urges him forward.

Ishigami’s brows scrunch together suspiciously, but the more he eyes Tsukasa, the more his expression settles, morphing into something curious, like Tsukasa’s the next device he wants to deconstruct and learn about.

“Sure,” Ishigami agrees. “If you’re nearby during the launch, you can come and watch.”

Tsukasa’s smile stretches, growing into an unfamiliar grin. “I can be around sooner than that.”

“Huh?”

“I mean… do bullies bother you a lot?”

Ishigami frowns. “They’ve started to bug me more recently, though they don’t always try to wreck my projects. I could probably come up with some countermeasures if I took the time, and my friend Taiju’s taken hits to save my work, too. But he never really fights back…”

He trails off, appearing troubled.

“I can protect you,” Tsukasa insists. “As long as I’m around, they’ll never touch you or your experiments again.”

“So, you wanna be my bodyguard?” Ishigami asks, slow and uncomprehending.

“I don’t know,” Tsukasa says. “I can help with stuff besides bullies, too.”

“Why would you do that?”

Tsukasa shrugs. “I want to. I thought everything you were talking about was interesting.”

“Really?”

“Yeah. I wanna know more.”

Something clicks in Ishigami’s curious stare. “It can be complicated. People usually don’t understand what I’m talking about. Taiju even gets headaches if I explain anything beyond the first-grade science curriculum.”

“I don’t really get it all, either,” Tsukasa admits. “But I understand what you want to do, and the idea behind your engine.”

There are a few beats of silence, then Ishigami makes an affirmative sound. “… alright. There are things I could use some extra help with. But I’ve gotta go home for today. I can’t make the repairs for this out here.”

While Tsukasa’s stomach drops, he tries to keep his disappointment from showing. “Oh. Will you come back here when you fix it?”

“Probably,” Ishigami says. “Don’t know how long it will take, though.”

Ishigami rises to his feet, staring back and forth between the dented device and a red wagon sitting nearby. Tsukasa stands as well, waiting for Ishigami to continue.

“… you’re strong,” he says. It isn’t a question.

“Yeah?”

“Can you help me move this?”

Tsukasa snickers. “Sure.”

He follows Ishigami’s directions, carefully lifting the parts and setting them into the wagon. While they’re pretty heavy, it’s nothing he can’t handle.

“You make it look easy,” Ishigami mutters.

Tsukasa shrugs.

Ishigami leans down to pick up the handle. He takes one step away before he pauses, turning to eye Tsukasa again. “My name’s Ishigami Senku. You can call me Senku, if you want.”

And just like that, the smile returns to Tsukasa’s face. He holds out a hand. “Shishio Tsukasa.”

Senku reaches out and takes it, giving it a firm shake, as if they’re making some sort of deal. He heads off when they let go, giving Tsukasa a small wave before he continues on his way, the remains of his science project in tow. Tsukasa stares after him for a minute, and when he finally walks home himself, it’s in somewhat of a daze.

What is it that had grabbed a hold of him then? How can he make that sort of promise to Senku when he should be looking out for Mirai?

It’s not like he owes Senku anything. They’d only just met, after all. So it’s odd how much he despises the idea of breaking his promise.

He wants to stay true to his word. He wants to see Senku again.

-

Tsukasa takes the same path home the following evening, gaze trailing over hills of green in hopes of finding Senku there. He sits near the riverside where he’d run into him, tapping his fingers against the dewy grass and watching each person who passes by.

It takes the first signs of the setting sun for him to realize Senku isn’t coming today. 

His fingers grip tightly onto the straps of his backpack as he trudges home, a hollowness in his stomach.

It’s fine. It was silly to assume he’d come back so soon. He’d said it himself, right? He didn’t know how long it would take him to fix his gas turbine.

So Tsukasa comes back the next day, and the next, and the one after that. And still, Senku doesn’t appear. Tsukasa can only chastise himself for getting his hopes up—for even caring at all. 

He wiggles the rusty key into the lock of their apartment a touch too aggressively and slams the creaking door shut, loud enough that it makes him wince. Mirai pokes her head out from the living area at the noise, tense until she identifies it’s Tsukasa returning. 

“You’re late again, brother,” she says, her voice small. 

Guilt furls in Tsukasa’s chest. He approaches her with a tender smile, laying a hand on her head affectionately. “I’m sorry. I promise I’ll make it up to you. Are you hungry?”

She nods rapidly.

“I’ll make dinner for us, and then we can do whatever you want for the rest of the night,” he says.

“Will you tell me a story?”

“Of course.”

“The Little Mermaid?”

“If that’s what you want,” Tsukasa says, fondly amused at the request. It’s by far her favourite, likely due to it being the only physical book they own, and she’s developed an obsession with mermaids as a result. He’s come home several times to her doodling on their bedroom floor, tiny colorful crayons scratching across the paper to depict herself with a mermaid’s tail. 

He decides he’ll have to try and snag more drawing supplies from the school as he makes his way to the kitchen. He notes an excess of wrappers, garbage bags, and bottles on his way there—and he grimaces at how much he’ll have to clean later—but there is no sign of their father. Last night, when Tsukasa had been trying to sleep, he’d heard the front door open and close, so he must have left then. There’s no telling when he’ll be back, where he’ll be going, or what he’ll even be doing. The interactions he bothers having with them tend to be sparse and vague.

They’re better off without him, and if Tsukasa were old enough to hold a job, he’d leave this place in a heartbeat.

When he opens the fridge and picks through the cupboards, he finds the contents scarce as usual. They’ll have to stick with something simple again…

He digs under his bed where he has a few cups of instant ramen stored, something he’d been able to afford for cheap with a 500-yen bill he found in an alley. He’d rather they have something more nutritious, especially for a growing girl like Mirai, but perhaps indulging in such a treat is exactly what they need tonight.

Mirai, at least, has no complaints, slurping up noodles and broth on their beat-up couch with a smile. The small television in their living room is playing re-runs of some old comedy, and Tsukasa wishes for the thousandth time they had their own movies to watch.

Mirai leans against him after dinner and he wraps an arm around her, staring straight ahead but not quite seeing anything.

“Brother?” she asks. “Are you okay?”

Tsukasa forces a smile. “I’m great, Mirai. Do you want your story now?”

She hesitates for a second, appearing conflicted before she nods.

Ah. He needs to get a better handle on himself. He can’t allow her to worry about him, too. He has to be strong for Mirai’s sake, like always. He has to have faith that he can continue as he always has. He doesn’t have room to yearn for anything more.

Stubbornly, he refuses to take the long way home the next two days, because it doesn’t matter. He has bigger responsibilities than whatever promises he’d made on a whim.

His father returns home then, drunk out of his mind as he slumps in front of the television and demands Tsukasa bring him another glass. Tsukasa grits his teeth and complies. Erupting into another screaming match would only unsettle Mirai further.

Going home the next night is much harder, so it’s for his own sake that he decides to indulge in the scenic route again.

And that day, a week after their first meeting, is when Tsukasa sees him again.

Senku is down by the river, a project that appears quite different from the last set up nearby. Senku is talking adamantly beside it, gesturing to another boy with short, spiky brown hair, who stares at him blankly.

Tsukasa’s heart thumps loudly in his chest, and before he can think better of it, he’s approaching the two.

“—acts as a coolant, see?” Senku is explaining.

“Uhm… sorta?” the other boy sputters.

“It means it’ll keep the temperature down, so it won’t explode on us.”

“That’s what you said last time and it still exploded!”

Senku waves a hand like it’s inconsequential. “That’s what experiments are for. Seeing what works and what doesn’t.”

The boy shakes his head, looking concerned. As Tsukasa inches closer, they catch on, whipping around to face him. Tsukasa stops in his tracks, uncertainty rushing through him.

“Oh, yo, Tsukasa,” Senku says, turning back to his project and fiddling with one of the dials. It’s so casual, like they’d interacted hundreds of times before, that Tsukasa is taken aback.

The other boy lights up, an easy grin spreading across his face. He moves toward Tsukasa, nearly vibrating with… excitement? “You’re Tsukasa?!”

“Yes,” Tsukasa says slowly. “That’s me.”

The boy sticks out his hand. “I’m Oki Taiju! Senku’s friend! I heard you’re really strong, and that you helped Senku last week!”

Taiju… Senku had mentioned someone by that name, and apparently, Tsukasa hadn’t been alone in recounting their previous meeting.

He smiles slowly, sparing a glance at Senku before shaking Taiju’s hand. “He told you that?”

Taiju nods. “Yeah! You sounded like a total superhero! Swooping in to save the day!”

“If he really saved the day, my project wouldn’t have been in shambles,” Senku mumbles.

“Aw, don’t be like that, Senku!” Taiju says. “You still had all the parts, right?”

Senku shrugs, looking back at Tsukasa. “That did help me in the long run. We were able to conduct the experiment with the gas turbine yesterday.”

“That’s good,” Tsukasa says. “How did it turn out?”

Senku smirks. “It was a total success.”

“It was super cool!” Taiju gushes. “It sent out a whole bunch of really hot air! It was like sitting in front of a fire!”

A knot forms in Tsukasa’s gut as he pictures the scene. “And nobody caused you any trouble?”

“Nah,” Senku says. “They’re not always around.”

Tsukasa nods. It’s for the best that nothing had gone wrong, yet a tiny part of him wonders if Senku had needed help, he would have thought of him again, if he…

The thought is squashed when Taiju makes an excited noise. “Wow! You’re so cool!”

Tsukasa blinks at him. “What?”

“You got so serious and worried about Senku’s experiments!” Taiju enthuses. “You’re a really nice guy! I totally knew it!”

Senku sighs. “Quit it with the overenthusiasm, you oaf. You’re gonna scare him off.”

“Oh! Sorry!” Taiju says.

Tsukasa’s smile grows fonder. “No, it’s fine. Thank you.”

“If you’re done babbling, it’s almost time to get started,” Senku says.

Tsukasa and Taiju trail to Senku’s side, Tsukasa taking in the new device curiously.

“What are you working on today?” he asks. “Another part of the rocket?”

“Uh-huh,” Senku says. “And it’s gonna be instrumental in bringing the whole thing together in the end.”

He takes off into an explanation, gesturing to what is a rough prototype for the rocket’s complete engine and how it is imperative to find a successful coolant and heat-resistant materials in order to keep it functioning when it is launched. He drops more technical jargon than Tsukasa is able to process, but he manages to stay relatively on track. Taiju, on the other hand, presses his palm to his forehead partway through, looking at if his brain is about to explode. It has Tsukasa biting back a grin.

“I’m anticipating a failure on this test, too,” Senku says, as he nears the end of his spiel. “But how it compares to past failures will teach us something new.”

And perhaps it’s that determination that Tsukasa finds himself mesmerized by—that makes him want to see Senku rise above every obstacle in his way.

“How can I help?” he asks, and Senku’s answering grin ignites a spark destined to fester further and further out of Tsukasa’s control.

-

After that, Senku and Taiju start relaying when they’ll be back by the riverside, and Tsukasa ensures he makes a beeline for them each time, often racing so quickly from his school building that he beats them both in arriving.

“But your school is way further away!” Taiju exclaims. “How fast can you run?!”

Senku tilts his head at him, curious.

Tsukasa shrugs. “Faster than most people.”

“That’s not a very concrete measurement,” Senku complains. “Maybe we should conduct a little experiment.”

“Like a race?” Taiju asks. “Ooh, that sounds awesome! Tsukasa, you’ve gotta race me!”

Senku’s own projects are set temporarily aside as the three set up perimeters for their impromptu competition. Senku opts to remain a spectator, pulling out a homemade pocket watch and directing Taiju and Tsukasa. When they start the timer, the two sprint across the length of the river, stopping at the overhang of the bridge they’d declared the finish line.

Taiju’s speed is downright impressive, his high energy clearly aiding him, and Tsukasa has to push himself hard in order to keep pace with him. Tsukasa barely wins the first race, and Taiju manages to overtake him in the second. They do individual runs after that, and Senku starts to rattle off statistics about footspeed and how their results compare to others in their age range.

“The stamina you two have is no joke,” he says. “If you keep training, you’ll grow stupidly unstoppable.”

“You hear that, Tsukasa?!” Taiju exclaims. “We should do this more often!”

“Sure. That sounds fun,” Tsukasa agrees, the energy Taiju is exuding utterly infectious.

He’s well-aware Taiju will commit to it, too. It didn’t take Tsukasa long to discover just how strong-willed he is. Like Senku, he becomes dead-set on anything he sets his mind to. He is not only determined to join the track team when he’s old enough, but the baseball and soccer teams as well.

It’s easy to like Taiju, especially as athletic competitions and leisurely games become a staple of their meetings. When Senku slips into his own head as he compiles results and makes adjustments to his work, Taiju and Tsukasa will sprint up and down the hill or kick around a soccer ball.

On one occasion, Tsukasa fumbles a kick and loses his footing, tumbling down the hill. He ends up covered in dirt and spitting grass from his mouth as he rolls to a stop beside where Senku is working. Taiju races over with a shout to check on him and Senku’s brows quirk in mild concern as he stares down at him. Tsukasa’s body aches and he’s probably received a few new bruises, yet somehow, all he can do is laugh and laugh and laugh until his belly hurts. Taiju helps him up, grinning along with him, and even Senku ends up snorting, an amused smile on his lips as he informs him he looked like an idiot when he fell.

But just like the first day they met, there are times when Taiju isn’t around. He’ll have a commitment at school or with his grandparents, and it leaves Tsukasa as the sole person sticking around Senku that afternoon.

In some ways, these days are Tsukasa’s favourite.

Tsukasa meets Senku at his school a few times a week, walking with him to the riverside or back to his apartment. The first couple times he drops him off, he leaves when Senku enters the front door before heading home himself, satisfied with simply hearing what Senku’s plans are for the night, even if he won’t get to witness them. And then, one day, Senku grabs his wrist and drags him inside with him.

It’s much nicer than where Tsukasa lives. Senku is settled in a safer part of the city in a decently-sized apartment. The furniture inside is relatively new and modern, there’s space to walk around and relax, and it’s clean—no garbage on the floor or questionable smells in the air.

“My dad’s been busy recently,” Senku says. “So, it’s no big deal if you come over. Taiju’s here a lot too.”

Tsukasa frowns, stomach churning at the implication. “Is your dad… what’s he been busy with?”

“He works as a university professor, and he’s been teaching some evening classes this year. I think he’s also sneaking in extra study time though, in case he has a chance to retake the astronaut exam.”

“’The astronaut exam?’”

“Uh-huh. He failed his first attempt because he couldn’t pass the clothed swimming test, and he complains about it all the time, so I know when they open up again he’s gonna apply.” Senku turns to Tsukasa, a determined light in his eyes. “Actually, I’ve been brainstorming ways to guarantee he passes! What do you think about a suit that will send electrical charges through your body when you’re in the water?”

Tsukasa frowns. “Isn’t that dangerous?”

Senku shrugs. “It’s nothing he can’t handle. And he’ll be thanking me when it helps him get through the test without embarrassing himself.”

As Tsukasa is ushered into Senku’s room—which looks akin to a lab given how many scientific instruments are strewn throughout—and attached to various wires for some experiment, he becomes attuned to Senku’s words and actions. Senku rolls his eyes a lot when he talks about his dad, explaining annoying habits he has and how he acts way too ridiculous to be a grown adult. But there is a focus in his eyes as he discusses the execution of his idea, and the smile that sneaks on his lips tells Tsukasa all he needs to know about their relationship.

It's foreign to Tsukasa, to say the least, and it leaves his chest feeling tight when he goes home that afternoon, tiptoeing to his and Mirai’s room so as not to wake his own father, who had passed out by the television.

Tsukasa goes to Senku’s apartment the next day too, sitting back and providing whatever assistance he needs. He listens to him ramble as he fiddles with different wires and mechanical parts and explains different theories he has, even if Tsukasa doesn’t understand a decent chunk of the words. It’s not just about the rocket Senku is working on—it’s dozens of projects, all at once. He deconstructs engines and electronics and appliances, picking apart their insides and using pieces of them in other ambitious builds.

Somehow, it’s more compelling to Tsukasa than any book he’s read and any program he’s seen on television.

Soon, Senku tasks Tsukasa with an important assignment: picking up the parts he needs from a nearby store for his project. He hands Tsukasa a large bill to do the job and shoves him out the door with a list.

It’s when Tsukasa is halfway there that his steps begin to slow, and the money in his pocket feels heavier. For the first time, he begins to doubt his own actions.

What will this be going toward? Just another in a long string of experiments that will end in failure, or with a creation that at the end of the day, provides no true benefit? If this were Tsukasa’s money, he could use it to buy a feast for himself and Mirai. They could have full, nutritious meals for a week and he might even have enough left over to afford her a new storybook—one that isn’t falling apart at the seams.

His hands clench into fists, and his body is suddenly on edge. For a minute, he debates running. It’s not like Senku knows where he lives and could track him down. It’s not like Senku doesn’t have more money to buy what he wants for himself later.

But then he remembers Senku’s smile—that mischievous grin he wears as he accomplishes feats most adults could never even dream of, and how he directs such a look at Tsukasa. He remembers how he’d handed Tsukasa the bill without hesitation, like he didn’t hold a single doubt that Tsukasa would return to help him.

He pushes open the door to the store, hands over the money, and dutifully carries back the slew of various parts, wishing his stomach weren’t twisting into complicated knots all the while.

When he arrives back at Senku’s room, Senku reaches for the parts immediately, and Tsukasa takes a step back before he can get his hands on them. Senku’s face scrunches up in displeasure, though when he meets Tsukasa’s gaze, his expression shifts.

He sighs. “What’s wrong?”

“Senku… is all of this worth it?”

“What’re you talking about? I thought you wanted to help me out.”

“I did,” Tsukasa insists. “I-I do, it’s just… these parts were expensive. What are you even using them for? A machine that’ll blow up or won’t work like it’s supposed to until you buy more and more? Isn’t it a waste?”

“A waste?” Senku repeats, incredulous. “Not a chance. Even if one experiment is a failure, as long as some part of it remains unscathed, it can always be reused for something else. And even if they’re beyond repair, we’ll still have gained knowledge, and humanity doesn’t get anywhere without knowledge. Any progress makes way for more progress.”

“I suppose,” Tsukasa mumbles.

Senku stares at him in silence for several seconds, then stands up from where he’s sitting and moves to his desk. “Leave that stuff over there and check this out. We’re gonna build something different today.”

“Like what?” Tsukasa asks.

“Dunno yet,” Senku says. “But it’ll be awesome, and when I’m done, you’ll never question the capabilities of science again.”

It’s Senku’s confidence that keeps Tsukasa at his side, the new materials forgotten as he hovers by the desk and watches. The drawers on either side are thrown open, revealing themselves to be overflowing with a mishmash of parts: there’s metal, wood, loose wires, gears, and more—all different shapes and sizes. They’re like extra pieces from puzzles that have already been solved, thus from afar, placing them together would only create a disjointed picture.

But Senku sees something Tsukasa doesn’t, a hidden masterpiece within a sea of randomness.

He sifts through the parts for a few minutes, humming to himself, until finally, inspiration strikes him. He pulls out a small wheel with interest, then digs until he comes up with three more, placing them on the table. There are two pairs, and the sizes are slightly different, one more akin to the tires on a vehicle and the other more old-fashioned.

He continues picking through the scraps until he has a whole plethora of items and tools before him, and he gets to work, not telling Tsukasa what he’s doing as he progresses. Tsukasa shifts between sitting on Senku’s bed, tapping his toes as he waits, and playing assistant, grabbing Senku whatever he needs when he requests it.

Thankfully, it doesn’t take him long to finish, and when he does, Tsukasa gawks in awe. On the floor of Senku’s room now sits a shoddy looking toy car. The wheels from earlier rest lopsidedly under a wooden piece that’s been cut into a shape resembling a car’s base, and above it is a clear plastic dome that doesn’t quite fit properly overtop, making the car’s body. Inside, Tsukasa can make out circuitry and batteries, and there is a small antenna rising from the back of it.

Senku hands him a controller that has a couple different buttons and a small joystick. He points them out to Tsukasa one at a time. “This will get the car going, that powers it down, and you use this to move it around.”

Then he waits, staring at Tsukasa expectantly. Tsukasa looks skeptically at the controller for a moment, then hesitantly clicks the button Senku indicated to start. There is a whirring from the car as it takes off, zooming across the room. Tsukasa reaches for the joystick, spinning it around before the car can crash into a wall, and his eyes widen in wonder when the car actually follows his command.

“Hmm, it’s faster than I expected. I can probably modify the controls a bit so we can adjust the speed, that way we won’t have to worry about—”

“Amazing,” Tsukasa breathes, too distracted with driving the car in circles to really comprehend what Senku is saying. “This is so cool, Senku.”

While he doesn’t look over to see Senku’s reaction, he hears the smirk in his voice when he speaks. “Of course it is. I promised you it would be, didn’t I?”

Excitement has stirred in Tsukasa’s chest and it’s difficult to taper it off. Maybe the car isn’t exactly useful and it definitely doesn’t look the prettiest, but it’s… fun. Unexpectedly so.

Tsukasa doesn’t allow Senku to take the controller away from him immediately, dodging his hands and easily avoiding all his attempts to snag it by hopping around the room.

When Tsukasa finally does relent, his cheeks hurt from grinning, and Senku rolls his eyes as he tinkers further with the car and controller, promising it’ll only be improved when he’s done with it. This time, it’s hardly a shock when this proves to be true.

It’s a gamechanger that tapping on one of the buttons extra times will gradually increase the speed, adjusting it to different settings he can easily click back and forth. Tsukasa sits cross-legged on the floor simply driving the car in repeated circles around him, mesmerized by it, as Senku fiddles with other items at his desk. It’s only as the oranges and purples of the sunset have faded to darkness that Tsukasa freezes, the car bumping pathetically into a wall as the time registers.

He shoots to his feet, grabbing his backpack by the door and reluctantly leaving the controller on Senku’s desk.

“Sorry, I’ve gotta head home. My sister will be wondering where I am,” Tsukasa explains. It’s the first time he’s mentioned Mirai to him, and he notices how Senku raises an eyebrow at this new piece of information.

He’s halfway out the front door when Senku calls his name.

“Tsukasa! Wait!”

Tsukasa pauses, and Senku approaches with the remote-control car in his arms. He holds it outward and Tsukasa blinks, uncomprehending.

“Keep it,” Senku says.

Tsukasa’s heart thumps loudly in his ears. “Huh?”

“I said keep it,” Senku repeats, and this time, it sounds more like a demand. “If you leave it here I’m only gonna take it apart again.”

Slowly, cautiously, Tsukasa takes the car and controller into his hands, holding them as delicately as a rare collectible. “You… are you sure?”

Senku shrugs, like whatever Tsukasa decides makes no difference to him. “I made it for you in the first place, remember?”

Tsukasa clutches the toy close to his chest, careful not to rustle any of the parts as he does. His throat feels strangely clogged up, so he nods shakily at first, then manages to force out an uneasy, “Right… Okay. Thank you.”

Senku nods, satisfied. He offers him a lazy wave as he heads off. “Uh-huh. See you tomorrow.”

And it sounds so inevitable when he says it, that Tsukasa will come back again and again, and he can’t find it in himself to doubt it either. He turns the car around in his hands as he makes the trek back home, fingers trailing over all the jagged parts that inexplicably came together. It’s ugly, there’s no doubt about that, but when he sets it up in his and Mirai’s bedroom later, and she becomes just as entranced with it as he was, laughing excitedly as she races it around, he can’t help thinking it’s beautiful too.

-

Spending time with Senku soon becomes a daily occurrence for Tsukasa, whether it’s at his apartment, by the river, or somewhere in-between, he can’t seem to be satisfied. So it’s no surprise that Mirai notices it too. She’s playing with an LED cube that Senku had given Tsukasa, that changes colour whenever you tilt it in different directions, when she finally confronts him about it.

In a small voice she asks, “Did you make some friends? Is that why you’re always home late now?”

It’s far from the first time he’s mentally smacked himself for leaving Mirai alone more frequently, but hearing the uncertainty in her voice makes it the most powerful blow yet.

“Yeah,” he says slowly. “I made two friends.”

They’ve never called each other that explicitly, so he hopes it isn’t too presumptuous to refer to them that way. Should there be a formal declaration for this sort of thing? He wishes he knew.

He doesn’t anticipate Mirai’s slow smile, or her little laugh. “That’s good. You always look so lonely, big brother…”

He shakes his head. “How could I ever be lonely with you here, Mirai?”

The look she shoots him showcases more skepticism than a five-year-old has any right to display, but the way her cheeks puff up and lips purse in a pout is too adorable to be offended by.

Tsukasa laughs. “Well, I’m sorry I haven’t been around as much. I’ll make it up to you, okay?”

Mirai perks up at that. “Like how?”

“Like…” Tsukasa hums, spinning ideas in his head before landing on the perfect solution. “How about you come meet them?”

“Really?!”

“Yeah,” he says. “I’m sure they’ll like you.”

Hopefully, at least. He’s talked more about Mirai since he first brought her up to Senku, and Taiju seems excited by the fact he has a sibling. He can’t imagine they would react too sourly if she tagged along with them, right?

“And I know the perfect time to do it,” he adds.

The occasion arrives a mere few days later. Tsukasa makes a beeline home, takes Mirai’s hand, and leads her to the pre-arranged meeting spot with Senku and Taiju. For this particular experiment, they’d needed to find a more private and open area out of necessity. At the edge of a park, near miles of forest, rests a quiet hill. Tsukasa lifts Mirai on his back halfway up, the trek steeper than either of them had anticipated, and each step is enunciated by the crunch of red and orange leaves on the ground below. Mirai wraps her legs around his middle and peeks over his head, squinting at the top of the hill and vibrating with anticipation.

He drops her back on her feet when they reach the peak, and Mirai sprints over to where Senku and Taiju are waiting in the clearing—Senku crouching low as he sets up his experiment and Taiju staring intensely. Taiju looks up as she approaches, rising to his feet with a grin. He waves a hand enthusiastically.

“Hey!” he calls. “You must be Mirai! Tsukasa told us you were coming!”

She nods excitedly. “Yeah! He told me it would be really cool!”

“Don’t get your hopes up too high,” Senku warns her. “This is only Mark 1.”

Tsukasa kneels beside Senku, greedily taking in the different components of the project. “Even if it doesn’t turn out how you’d hoped, I’m sure this will be a day to remember.”

At that, Senku grins. “Sure. No one gets anywhere without taking a concrete first step.”

Tsukasa nods. The fact Senku had managed to make it this far is an achievement in and of itself. The rocket before them is smoother and sleeker than Tsukasa expected, every piece slotting together with precision. It’s a smaller scale version of the ones Tsukasa has caught glimpses of in textbooks and on television, but he knows it’s no toy. Inside is all the circuitry required to properly launch it, each component studied extensively by Senku.

Senku had explained that the individual pieces are functional on their own; the risky part comes when they’re put together like this. He’d had to use many alternative materials from what normal rocket designers utilize since he’s only an amateur, thus, the chances of something malfunctioning is high. The thing is, they’ll never know where the problems lie until they actually test it.

Senku stands up, hands on his hips and eyes glittering. “Alright, time for takeoff.”

He directs Taiju, Tsukasa, and Mirai to stand a fair distance away, dragging the launch button—connected by a long wire—along with him. Tsukasa takes Mirai’s hand when she gravitates back to his side, and his heart is warmed by the intrigue in her expression. 

“Ooh! Are we gonna do a countdown?” Taiju asks. “Maybe we can each yell a number and Senku can call ‘go’!”

Senku shrugs. “Why not? You wanna start it off, Tsukasa?”

“Alright,” Tsukasa agrees, lips curling into a smile. When he speaks again, he raises his voice to a shout. “Three!”

“Two!” Mirai chirps.

“ONE!” Taiju yells.

“And takeoff!” Senku finishes, slamming down on the big red button.

The rocket sputters to life, spewing out combustion as it shoots upward, breaking out of the arms holding it to the launch pad. For a fleeting moment, Tsukasa’s stomach lurches, every inch of his body vibrating at the marvel he is witnessing.

And then, it all goes wrong.

After reaching several feet above the launch pad, the rocket tilts sideways, shooting off horizontally in their direction. Taiju yelps, and Tsukasa yanks Mirai behind him, but it doesn’t come their way as it seemed, instead turning and whirling in a quick circle. After it completes the rotation, it explodes, a boom cracking in the air and sending debris flying onto the grass below them.

The fear and shock on Senku’s face melts after a few pointed seconds of silence, and he sighs. “Well, I did say our chances of a successful launch today were seriously low.”

Taiju shivers. “I seriously thought that was gonna kill us, Senku!”

“It ten billion percent wouldn’t have killed us,” Senku insists. “There’s a reason we kept a safe distance.”

Tsukasa looks down at Mirai, whose eyes are as wide as saucers and locked on the spot where the rocket had exploded. “Are you okay, Mirai?”

He scans her body, brows furrowing in concern. She hadn’t been scraped by any of the debris, had she? Or was such a display simply too much for her?

Thankfully, she nods and finds herself again. She hops on her toes, examining the materials on the ground and the smoke still lingering in the air. “That was so scary! But really exciting! Can we do it again?”

Senku snickers. “We’ve gotta rebuild it from scratch before we can do that.”

Mirai frowns. “Oh. Does that take a long time?”

“Probably,” Senku says. “One of my main issues is finding an obtainable heat-resistant material that can withstand the pressure of the launch. I thought I’d made progress, but it doesn’t seem like I’ve gotten one millimetre closer to where I need to be. Fixing what went wrong will take a whole lot of adjustments. Maybe I could speed along the process by contacting a professional to see if they could give me a few tips on how to achieve this as an amateur…”

Mirai blinks at him in confusion, clearly not following after the first few words. Tsukasa chuckles, watching as Senku taps his chin and continues to mumble under his breath. It seems not even a failure this grand can dampen his spirits.

Taiju crouches down next to Mirai, smiling kindly. “Don’t worry! No matter how long it takes, you can totally come to the next launch too!”

“Really?”

“Yeah! We’d love to have you!” Taiju enthuses. “And today’s fun isn’t over yet either!”

Mirai leans forward, intrigued. “It isn’t?”

“Nope! Check out what I brought!” He lifts a soccer ball to showcase to her and she “ooo”s appreciatively. “Do you wanna play with me?”

“Yes!” She swerves to stare up at Tsukasa. “Is it okay if I play?”

“It’s no problem,” Tsukasa says.

“Awesome! Then, let’s head over to where there’s more space,” Taiju says, pointing to their left. Mirai nods along, trailing after Taiju like a little duckling when he runs. Tsukasa keeps an eye on them as they go, and it’s like the whole world becomes less… heavy, as he watches the two of them kick the ball back and forth, radiating joy all the while.

“Jeez,” Senku mumbles, drawing Tsukasa’s attention his way. He’s rubbing the inside of his ear with a finger, lips pursed amusingly close to a pout. “It’s not like we’re done here. Cleaning up this mess is gonna be a whole lot of work.”

“Let them have their fun,” Tsukasa insists. “I’ll help you with the rest.”

“That’s noble of you,” Senku muses. “Do you have big brother instincts written into your DNA or something?”

“I don’t know,” Tsukasa replies. “You’ll have to tell me.”

“Alright,” Senku says, standing a little straighter. “I’ll give you a lesson as we clean this up.”

While Tsukasa doesn’t hold much interest in human genetics, he doesn’t tire of hearing Senku talk, and keeps an ear open as he picks up hunks of metal from the grass. Shards have been scattered all over the area, and most pieces he dumps into Senku’s wagon are broken beyond repair. Senku is clearly displeased about the severity of the explosion, his explanation on the shape of DNA—or deoxyribonucleic acid, as is apparently its true name—wavering as he picks through some pieces. Before Tsukasa can ever check in with him, however, Senku continues right where he left off, like nothing had happened.

Ah. That’s right. Even if Senku falters, he won’t allow any number of setbacks to slow him down. That’s just who he is.

“Do you wanna know one of the craziest things about DNA?” Senku asks, when they’re settled side by side, digging tiny wires out of the dirt.

“What?” Tsukasa says, the fascination in Senku’s voice infectious.

“The DNA within any one human being and another is 99.9% identical,” Senku explains. “Every person has the same blueprint for development. Which means we’re all connected way more than we think.”

Tsukasa’s fingers pause in their search. “So… we’re only 0.1% different?”

“From a genetic standpoint, yeah.”

“That’s…” Tsukasa struggles to find his thoughts, but can’t quite decipher what about this has him so fascinated.

“See?” Senku says. “Told you it was crazy. That tiny number helps define who we are. Obviously personality isn’t crafted just from what’s inside us, since our environments have a pretty big impact too, but that unique percentage is a factor in shaping our abilities, health, and behaviour.”

“So, what you’re saying is… I probably don’t really have big brother instincts in my DNA?” Tsukasa asks teasingly.

“You could,” Senku insists, “but it’s probably not solely based on that if you do. I can’t tell you for sure. I don’t know everything, you know, and neither do all the other scientists out there.”

“But you’re using what you do know to learn more, right?” 

Senku brightens. “You’re catching on.”

Tsukasa laughs. “You know, the world is so much cooler when I’m with you.”

“Huh? What are you talking about?”

Staring into Senku’s doubtful gaze, Tsukasa almost wants to lose himself to laughter all over again. Maybe he’s the one who’s being silly here, but when he’s with Senku, he finds himself believing in the impossible.

“I just know you’re going to do amazing things,” Tsukasa offers.

“Of course I am,” Senku says. Fondness curls in Tsukasa’s belly at the declaration, and he is content as he goes back to picking for scraps.

There is a long stretch of silence before Tsukasa speaks again.

“I really like hanging out with you,” he admits quietly.

Another pause, Senku’s hands hesitating in their search before moving again.

“… you’re pretty cool to hang out with too,” Senku says, matching his volume.

“Even if I don’t know much about science?” Tsukasa teases.

Senku rolls his eyes. “Duh. No one knows everything right off the bat, and not understanding Newton’s law of universal gravitation or Einstein’s theory of relativity doesn’t mean you can’t do other things. Scientists may be the ones with the brains, but they can’t do anything without people to help build their projects, listen to their ideas, or haul their heavy equipment. That 0.1% difference is what gives everybody their own strengths, and it’s only by using the strengths of all people that we can make the world work.”

The explanation gives Tsukasa pause. While he’d assumed his company was helpful to Senku and that Senku was interested in Tsukasa’s strength and speed, he hadn’t assumed he was… that important.

Tsukasa opens his mouth, a question on the tip of his tongue, when Senku speaks again. “Anyway, I think we’re done finding stuff here. Let’s go look over there.”

Senku stands up, moving to another spot nearby and squinting into the grass. Tsukasa sighs, a heaviness in his chest as he follows after him. It is not often that he is truly afraid. He can’t be. But knowing Senku’s feelings may not match his own is too terrifying to seek the answer to, so he remains quiet.

It takes another half hour for them to finish gathering the materials, and Tsukasa volunteers to pull the wagon down the hill while Taiju shows Mirai the best way to roll down it without getting hurt. Her sundress is covered in crumbled leaves and stains when she stands back up, but the glee on her face more than makes up for the trouble it will take to get them out.

“We’d better get going now,” Tsukasa says, offering the handle to Senku. “I have to get Mirai home for dinner.”

“Well, you can bring her back any time!” Taiju encourages.

“Thank you, Taiju,” he says. “Would you like that, Mirai?”

“Yeah! It was fun!” she exclaims. “Thanks for letting me come!”

“Sure,” Senku says with a shrug.

“And thanks for being my big brother’s friends!”

Tsukasa’s body goes ramrod stiff. Turns out, he would be getting that unwanted answer after all, and he couldn’t even chastise Mirai for her assumption when he’d been the one to state his feelings so blatantly to her.

“Aw, you don’t need to thank us for that!” Taiju exclaims, his grin brightening, and while Tsukasa isn’t exactly surprised by his answer, it stirs a warmth in his heart.

A warmth that erupts into an inferno when Senku speaks up, a smirk on his lips. “Thanks for letting us steal him so often. Our group’s a whole lot stronger with him here.”

And somehow, Tsukasa knows he’s not talking about physical strength alone.

Mirai nods hastily, and Tsukasa’s eyes sting as he thanks his friends—his friends—once again.

And as he leads Mirai away and she blabbers excitedly to him the whole way home, he can’t help feeling like maybe she had been right all along about him. He’d been lonely before, but now, that was finally changing.

-

Unfortunately, life doesn’t stop being difficult. Even with Mirai joining Tsukasa’s outings with Senku and Taiju on occasion and gaining toys in the form of Senku’s inventions, their situation doesn’t magically fix itself.

It’s obvious when the door slams in the dead of night and Tsukasa’s eyes snap open in the darkness. He’s trained himself to no longer flinch at sudden loud noises, and Mirai is thankfully a heavy sleeper, but the curses coming from the kitchen still have dread curling low in Tsukasa’s stomach.

He forces himself to crawl out of bed, ensuring he is alert and standing tall before he leaves the room. He locks the door behind him and creeps down the small, creaky hallway into the living area.

His father is half-slumped over the table, facial hair scruffy and eyes bloodshot. There’s a half-empty bottle next to him and Tsukasa is certain it’s not his first. When he turns to him, it’s with an aggravation he is accustomed to, a step below the indifference he receives most often.

“There’s no food in the fridge,” he complains.

“We don’t have any money,” Tsukasa snaps.

His father groans slowly. “Wallet’s on the counter. Take out some bills and stock up tomorrow.”

Tsukasa doesn’t have to be told twice, digging into the wallet and taking all the bills from the pocket.

“Whoa, whoa, I said some, kid!”

“Do you want a full fridge or not?!” Tsukasa shouts. “This is barely enough to feed the three of us as it is!”

“Fine, fine, whatever,” his father grumbles. “But you better get some good stuff this time.”

“I’ll get what we can afford.”

He doesn’t know where his father even gets this cash. Probably from gambling. He bets all the credit cards he owns have long reached their limits, and paying off whatever interest had accumulated for late fees probably took all the earnings he made during “work”. Not that Tsukasa has been informed what he even does for a living.

His father rolls his eyes. “Don’t give me attitude. And whatever you make for dinner tomorrow, you better leave a plate for me.”

Tsukasa’s fists clench at his sides. “Make your own damn food.”

He turns on his heel, intent on stomping his way back to the bedroom, when he’s stopped by his father grabbing his wrist. He grips him hard, fingers digging relentlessly into his skin, and Tsukasa winces.

“Don’t talk back to me, or you and Mirai can find somewhere else to live,” his father threatens. He laughs. “Oh wait, you can’t do that. You’re just a kid, right?”

Tsukasa grits his teeth together and shakes his arm hard to dislodge himself. His hands begin to tremble, itching to throw a punch. When Tsukasa hits his growth spurt, he’s certain he’ll close the gap in their height difference and be the one leering over his father instead. And even without that advantage, he could surely take him in a fight, here and now.

But while he could survive on the streets if he’s evicted, he won’t force Mirai into that life.

So instead, he shuts his eyes, counts to three, and continues on his way, his father’s laughter echoing in his ears as he locks the bedroom door. He slides against it, tears of frustration pricking his eyes. He pulls his knees to his chest and hides his face against them, fighting back the urge to rush back out there and unleash his fury on something, anything.

When Mirai wakes up the next morning, he smiles at her like usual, pulling down the sleeves of his hoodie and telling her to stay in their room today. He pulls out a snack he’d hidden for her breakfast and heads to school.

This is the life he’d been brought into. There’s no changing it.

He takes Mirai with him to the grocery store after his classes, stocking up on as much as possible. He’s grown skilled at finding decent deals, and with enough strategy, they might actually be eating well for a couple weeks, depending on how much his father indulges. Tsukasa makes chicken, rice, and vegetables for dinner, leaving a plate for his father who is snoring in his own bedroom. He only truly breathes again when Mirai gushes about how good it tastes.

He knows it’s not much, but it’ll have to do.

The next day, Senku asks him to come over—a more frequent arrangement with the approaching threat of winter—and he agrees quicker and more eagerly then he should have. Senku gives him that intense look, like he’s analyzing him, and ultimately says nothing. It’s better that way.

“What are you working on today?” Tsukasa asks.

Senku rubs the back of his neck. “I hit a roadblock with the rocket so I’ve been doing research to find new experiments to test, but I don’t have any materials for them right now.”

“Oh,” Tsukasa says. “So, what’re we doing?”

Senku grins. “You said you don’t watch TV, right?”

“No, not really.”

“So, you’ve never seen Doraemon?”

Tsukasa shakes his head.

“Then, we’re watching Doraemon,” Senku declares.

He gestures for Tsukasa to join him on a comfy-looking couch in the living area, set up in front of a television twice as big as the one his father monopolizes. Senku pulls out some DVDs and slides one into the player before settling next to Tsukasa, telling him the basic premise of the show.

It’s a series geared towards kids that’s centered around a time-travelling robotic cat. The cat helps out a boy using a variety of strange gadgets, and its use of technology is the tip off to why Senku must be so fond of it—even if it’s not nearly as advanced with science as he is.

It’s fun. It’s not often they hang out and just… relax like this, and Tsukasa thinks he could get used to it. Especially with Senku rattling off interesting trivia about the show’s universe and its behind the scenes production.

They’ve blazed through five episodes when there’s a click at the front door. Tsukasa’s head whips in its direction and he watches intently as a man enters the apartment. His hair is white with dark ends nearly reaching his shoulders, he has wrinkles around his brown eyes, and when his gaze lands on Senku and Tsukasa, he appears surprised for a moment before the look levels out into fondness. He carries two grocery bags in his arms that he sets by the door. 

Tsukasa tenses, sitting up straighter and remaining quiet as the man approaches. 

“You’re home early,” Senku remarks. 

Senku’s father shrugs. “I cancelled my evening class so we could have dinner on time for once!”

“That’s irresponsible.”

“Oh, c’mon, what’s wrong with wanting to spoil my son every now and then?” he asks. His gaze drifts to Tsukasa, and he offers him a smile. “And my son’s friends, too! Sorry, I don’t think we’ve met yet, I’m Ishigami Byakuya, Senku’s dad.”

“Shishio Tsukasa,” Tsukasa offers curtly.

“Ah, Tsukasa! I was wondering when I’d finally get to meet you,” Byakuya enthuses. “Senku’s told me about you!”

Tsukasa turns to Senku, who has stuck his hands in his pockets and is glaring pointedly at the television screen.

Byakuya continues, “You’re welcome to stay for dinner if you’d like. It’s gonna be quite the feast!”

Tsukasa hesitates. He doesn’t usually leave Mirai alone past dinnertime, and while he’s certain she’s smart enough to handle her own meal prep, the idea ties his stomach into knots. At the same time, the very thought of going home now is nauseating. “I…”

“He’ll stay,” Senku says.

“Sen—”

“Great!” Byakuya interrupts. “Do you need to use the phone to let your parents know you’ll be staying late?”

Tsukasa grits his teeth. “No. That’s fine.”

Byakuya nods, seemingly satisfied with that answer, and continues on his way to the kitchen. Tsukasa waits a moment before he faces Senku, lightly smacking his arm and glaring hard.

“Why did you say that?” Tsukasa snaps. “I can answer for myself.”

Senku rubs at his arm, displeased. “Yeah, but there are still more episodes I wanna show you, so you can’t leave yet.”

“But, Mirai—”

“You can go home when dinner’s over and bring her some leftovers,” Senku says. “My dad won’t mind.”

Tsukasa swallows back a lump in his throat.

“Will she be okay?” Senku asks, voice a little softer than before.

“I think so,” Tsukasa says. “But I have to leave right after.”

Senku shrugs. “I already said you can. I’ll make sure my dad doesn’t stall you on the way out.”

Tsukasa nods, settling slowly against the couch as Senku restarts the show. It’s more difficult to focus this time around, even with the bright colours and silly scenarios on the screen tempting him back into relaxation. There are clangs and bumps as Byakuya works around in the kitchen, the sound of the fridge humming as it opens and closes, and the beeping of timers. Tsukasa strains to hear each one and splits his attention once Senku actually begins to speak again. He draws him into explaining how a crazy gadget on the show could likely never be created in reality, but with how Senku gushes about it, it’s clear he finds the concept interesting nonetheless. 

Tsukasa’s shoulders begin to ease, his lips twitching back up. “You know, he’s really cute.”

“Huh? Who?” Senku asks.

“Doraemon.”

Senku wrinkles his nose. “It’s not about being cute.”

“I know,” Tsukasa says, watching as the character prances about onscreen. “But he still is, isn’t he?”

It’s hard not to fall for a creature so adorable. If it weren’t impossible, Tsukasa would reach into the TV and cuddle him. The very idea has him feeling fuzzy.

“Well, I guess so,” Senku relents. “He is purposefully designed like a friendly animal mascot to appeal more to kids.”

“It’s probably not just for kids,” Tsukasa argues.

They go back and forth for a few minutes debating the extent of Doraemon’s cuteness as the episode continues, and the scent of something savory begins wafting in from the kitchen. It’s enough to keep Tsukasa placated even as the credits roll for their current episode and the next one picks up immediately after. He even feels his stomach rumble once or twice. Maybe, it wouldn’t be so bad to stay here and try a bit of whatever Byakuya is cooking. Surely there isn’t some kind of catch if Senku—

A piercing sound screeches through the apartment, prompting Senku and Tsukasa to cover their ears. Senku rises to his feet, perturbed as he follows the noise to the kitchen. Tsukasa is hot on his heels, his heart thumping in his chest. When they enter the room, it’s to the sight of Byakuya waving a dish towel in the direction of the stovetop which is expelling a cloud of smoke from one of the pans. The fire alarm continues to blare overhead, and Byakuya flashes them an apologetic smile.

“Ah, don’t worry, you two! Just hit a bit of a roadblock in here, I’ll have it fixed up right away!”

Senku sighs, moving to grab a chair from the dining table. “What did you burn this time?”

“Ouch, no need to be so harsh, Senku! You’re going to embarrass me,” Byakuya whines. “I don’t screw up that often! Though I can’t say cooking is my strong suit.”

Senku stands atop the chair, stretching his hand towards the alarm to try shutting it off. He’s on his tiptoes and can’t quite reach the button, so Tsukasa nudges him aside and climbs up himself, reaching up to click off the alarm with ease. Senku gives him a look and Byakuya nods his gratitude, shifting back to the stovetop to try and save whatever had been on fire.

“What are you making?” Tsukasa asks, peering into the pan as Senku returns the chair.

Byakuya smiles down at him. “It’s supposed to be beef teriyaki, though it’s a little bit of a mess right now.”

Tsukasa hesitates, staring at the blackened food being swished around for a few seconds before he slowly asks, “Do you need any help?”

“Oh, that’s not necessary!” Byakuya assures him. “I’ve got this.”

“Just tell us what to do,” Senku insists. “If the kitchen burns down, we won’t have a home or dinner.”

“I suppose I did take on a little much…” Byakuya says. “Alright, I guess it would be a big help to have a couple assistants.”

Byakuya instructs Senku to get the rice going in the rice cooker and Tsukasa to chop up some carrots as he continues to struggle with the beef teriyaki. Tsukasa finishes his task quickly and stares contemplatively at the other vegetables on the counter.

“What’s the plan for these?” Tsukasa asks. “A stir-fry?”

Byakuya rubs the back of his neck. “That was the idea.”

“I can get it started,” Tsukasa offers. He’s had more than enough experience throwing all they had in the cabinets and fridge into a pot and whipping up a meal out of it, and with the quality of these ingredients it should be far simpler than usual.

“You don’t—” Byakuya starts.

Senku opens the fridge. “You can use whatever you need in here for it too, Tsukasa.”

Byakuya’s protests die in his throat as Tsukasa commences his new assignment with the help of Senku. Soon enough, he has a slew of vegetables, sauces, and spices all piled together in a pot, sizzling as he stirs them around with a wooden spoon.

“Wow!” Byakuya says, leaning closer. “That already smells great! You’re quite the talented chef, Tsukasa!”

Tsukasa’s cheeks burn. “Not really.”

“Oh, come on, no need to be modest, you’re already doing way better than I am, and I’m a seasoned man,” Byakuya jokes.

“There’s a lot you could be better at,” Senku points out.

Byakuya gasps, mock offended, and he and Senku begin to bicker back and forth. Strangely though, there isn’t a hint of malice to it. In fact, Byakuya is undeniably fond as he speaks with his son, especially as it eases into conversation, Byakuya asking Senku about his day and the results of his recent experiments. Senku is happy to ramble on about that, and the pride on Byakuya’s face is so evident Tsukasa begins to feel like he is intruding.

That is, until Byakuya takes the spoon from Tsukasa’s hand and nudges him gently away from the stove. “Thank you for all of your help, Tsukasa, I really appreciate it. But why don’t you and Senku go back to watching your show now?”

Tsukasa blinks, surprised. “I can finish the stir-fry first.”

“I know you can,” Byakuya assures him. “But I’m still the adult here, right? That means I’ve gotta be the responsible one. You two go have fun! With all your help, it looks like dinner will be ready soon.”

“Are you sure?” Tsukasa asks, voice coming out a lot quieter than he intended, and an odd sensation churning within him.

“Ten billion percent,” he answers, and Tsukasa wonders whether Senku had picked up that phrase from his father, or his father had adopted it in honor of Senku.

Senku pulls Tsukasa by the wrist, nudging him back toward the living room. “He’s not that incapable. He can handle it while we finish our episode.”

As promised, it’s only a few minutes after the screen fades to black that Byakuya is calling them back into the kitchen, and when Tsukasa enters the room, he pauses as he takes stock of the dining table. Byakuya had been right to call it a feast, at least by Tsukasa’s standards, because even after helping, he isn’t prepared for the variety of dishes spread out there. There’s the beef teriyaki—a little charred but piled high on a plate—mounds of rice, the vegetable stir fry, miso soup, and grilled fish. The portions are all large enough that each of them could probably have seconds and thirds of everything if they wanted.

Tsukasa is directed to a seat next to Senku on one side of the table, while Byakuya settles on the other. The Ishigamis begin to dig in immediately, spooning the different components onto their plates. Tsukasa waits a minute, then follows their lead, grabbing a hefty amount of each item. It would be rude to let anything go to waste, right?

“So, Tsukasa,” Byakuya says, after he finishes chewing his first bite. “How did you like the show?”

“It was fun,” Tsukasa answers.

“It sure is,” Byakuya agrees. “And isn’t Doraemon just adorable?”

Tsukasa turns to Senku, a tiny smirk pulling at his lips, and Senku rolls his eyes as he stuffs rice into his mouth.

They talk about the episodes they’d watched for a few minutes before the topic shifts, Byakuya’s attention now solely on Tsukasa. He asks him how he likes school and what his favourite subjects are. Tsukasa shrugs, mentioning the high grades he’s achieved and that many subjects hold his interest in different ways.

“I like reading a lot,” he adds. “It helps me find new stories to share with my sister, Mirai. And I am starting to get more into science. But I’m probably the strongest in Phys. Ed.”

Senku nods encouragingly. “That’s an understatement. He’s got speed on par with Taiju, and probably even more strength. Anyone lucky enough to get on Tsukasa’s team is almost guaranteed to win.”

“Do you do any sports?” Byakuya asks. “It sounds like you’d be great on the track team!”

Tsukasa shakes his head. “No, I’m not on any teams.”

He really doesn’t have time to indulge in activities like that.

“Ah, well you’re still young!” Byakuya says. “Maybe once you start middle school you’ll find one you want to try out for! Is there anything you think you might enjoy?”

“I’m not sure, but… I’m a good fighter,” Tsukasa offers.

“That’s cool. Do you take any lessons, like karate?”

“No, but I’m interested in different fighting styles.”

Byakuya nods and points his chopsticks toward him. “I see. Did you get those bruises there from training?”

Tsukasa’s gaze darts to where Byakuya is indicating, stomach dropping when he notices his sleeves had slipped down his wrist while he was reaching for more food. The dark purple bruises imprinted on him there are on full display.

His throat grows tight with a panic he struggles to discard, and he offers an uneasy smile as he pulls his hand away. “Yes. Some classmates and I were messing around.”

A strange look crosses Byakuya’s face before his bright disposition returns, and he continues to chew on his own food like nothing had occurred. “Kids are really rough sometimes, aren’t they? Make sure to be careful when you’re fighting, even if it’s just for fun.”

The conversation moves along swiftly, and Tsukasa breathes out a quiet sigh, sinking back into his chair. He focuses on his plate and the food remaining there, lifting his fork to his lips and savoring the new flavours that dance on his tongue.

The meal needs… a lot of work, to put it nicely. The beef teriyaki is far too salty and pieces of it are charred and difficult to consume. The fish isn’t much better. So, why is it that with every bite, Tsukasa likes it more and more?

“I know it’s not great,” Byakuya says, smiling sympathetically as Tsukasa pulls a tiny fish bone from his mouth. “Next time you’re over, I’ll work hard to make you something better.”

Tsukasa freezes, chopsticks stilling in the air on their way to a clump of rice. “Next time?”

“Sure,” Byakuya says. “I doubt this is the last time I’ll see you over here, right?”

Senku raises an eyebrow at him, like such a thing had already been a guarantee.

Tsukasa’s chest tightens. “Y-Yeah. Yeah, I’ll be back.”

“Then I’ll still have a chance to redeem myself,” Byakuya says, chuckling. “Or maybe I should admit defeat and take you out for ramen with us instead. That will impress you for sure!”

The squeezing inside Tsukasa becomes more intense, until it is difficult to breathe normally. The world around him grows fuzzier around the edges, like he— like he—

“Tsukasa? Are you alright?” Byakuya asks, concern creeping into his voice.

Oh.

He’s crying.

Tsukasa wipes at his eyes frantically, swallowing hard as he tries to force away further tears. Byakuya is staring at him so sympathetically that it makes Tsukasa’s face hot, and even the unreadable expression on Senku’s face cracks a little, making way for something gentler.

Tsukasa nods, voice shaky as he forces out a response. “I-I’m okay. I just… can I—would it be okay if I bring Mirai next time?”

Byakuya’s mouth drops in surprise, and Tsukasa would be embarrassed if not for the desperation clawing inside of him. If he could be so lucky… if he could get a warm, full meal and such friendly company, then the least he could do is allow her to have it too.

“Sure, why not?” Senku answers.

Byakuya and Tsukasa’s heads swish in his direction.

Senku shrugs, expression back to neutral as he chews on a piece of beef. “What? It’s not like that’s a problem, right?”

Byakuya’s shock fades, and he chuckles. When he turns back to Tsukasa, the look in his eyes is so kind that Tsukasa risks tearing up all over again. “No, of course not. I’d love to meet her! Tell her she’s welcome to join us anytime!”

Tsukasa’s throat is clogged up, and he sniffles pathetically. They say it like it’s easy. Like such an offer is merely common decency. Like this is simply the way the world works. And while he cannot begin to express even an inch of the gratitude that has washed over him in waves, he does manage to muster up a broken, “Thank you.”

“It’s the least I can do,” Byakuya assures him. “You’ve been looking out for Senku, right? He told me you’ve helped him with bullies.”

Tsukasa nods. Fortunately for Senku, they don’t come by often, but on the occasions they do show their ugly faces, Tsukasa is quick to scare them off as he’d promised.

“It’s no problem,” he insists. “He’s my friend. I’ll always protect him.”

“Thank you for that,” Byakuya says. “Really. It’s reassuring that Senku has such great people in his corner helping him out. And I know he’s been really happy to have you around too.”

Senku coughs awkwardly, muttering something under his breath about not needing protection, and that his old man is exaggerating. It prompts a surprised laugh to bubble up from Tsukasa’s throat, one that leaves him feeling lighter than before, and soon, Byakuya is laughing along with him. Just like that, the atmosphere shifts again, and the rest of dinner is easy, like nothing strange had ever occurred at the table.

And as Tsukasa walks home later with a bag of leftovers in his arms, he can’t help smiling at the pinks and oranges of the setting sun as they paint the sky.

His life is still far from a fairytale, but maybe, under the right circumstances, things can get better.