Work Text:
You’re in that awful half-sleep where your brain is awake enough to be mad, but your body has completely unionized against movement. The hut smells faintly like ash and old straw. Your blanket is twisted around your legs.
You’ve slept maybe four hours, tops.
Then—
Knock. Knock. Knock.
It’s not polite. It’s not urgent.
But, it’s definitely got intent.
You groan into the pillow. “Go away.”
The knocking ceases.
You smile faintly. Victory.
Unfortuneatly, any sense of complacency is shattered once you hear a faint, fizzing noise, followed by what sounds like metal falling on the floor.
The door creaks open, your doorknob laying still on the dirt.
“Incorrect response,” Senku’s voice announces. “The correct answer was ‘come in, genius.’”
You don’t even look up. “Did you just melt my lock off?.”
“Good luck replacing that,” he declares unceremoniously, footsteps scuffing in. “I used a thermite mixture— Think Breaking Bad.”
There’s a very loud thump followed by several smaller ones, then an irritated hiss of breath like someone just lost a physics argument.
Against your will, curiosity drags you upright.
Senku is standing in the middle of your hut like a poorly balanced supply cart. He’s juggling an obscene number of items—fabric slipping off one arm, cured meat dangling by twine, flowers shedding petals onto the floor. Something rectangular is tucked under his elbow. And dominating the whole mess—
A massive cake.
Like, offensively big.
It’s frosted thick, dark, and glossy, like someone went feral with cocoa and sugar and zero restraint. Senku’s trying to hold it like it weighs nothing, but the way his trembled wrists are angled says otherwise.
You sit up fully now, blinking sleep from your bleary eyes.
“…what flavor is that?”
Senku freezes.
Then he slowly turns his head toward you, red eyes flat with disbelief, “…What flavor is it,” He repeats, almost to himself.
Then,
There’s a beat of silence as Senku stares at you.
“Wow,” he says. “You’re not even gonna ask how we pulled this off in the middle of the Stone World? No ‘is this poison,’ no ‘did someone die for this,’ nothing?”
“Correct,” you say. “Because if I ask how, I’ll be absolutely dumbfounded for the next week, and I don’t have the energy to process anything before noon.”
He scoffs. “Unbelievable. I coordinated half the village, violated at least three conservation principles, and you go straight to flavor.”
“Senku,” you say patiently, “there is a cake. In the Stone World. Read the room.”
He clicks his tongue, adjusts his grip, and answers anyway.
“Coffee.”
Your brain lags for half a second.
“…coffee?”
“Coffee.”
You sit up so fast the blanket slides off your shoulders. “As in coffee coffee? Beans? Roasted? Ground? Not ‘this vaguely bitter root reminds me of caffeine’ coffee?”
“Relax, skeptic. Real deal.”
“How.”
“Ask Francois. I’m not touching that chain of miracles with a ten-foot pole. I stopped asking questions when the answer started sounding like Mise en place with a touch of Reste en dehors de ma cuisine.”
You decide to ignore the blatant insult spewed in French.
You swing your legs over the bed, fully awake now. “You’re telling me I went to sleep in the Stone Age and woke up in a café.”
“Don’t get used to it,” he chuckles. “This is a one-time flex. Maybe once a year if you’re lucky—assuming the Earth keeps orbiting the sun at a predictable rate and I continue arbitrarily assigning meaning to one specific rotation.”
He finally starts unloading everything, setting the cake down with exaggerated care.
“Dress,” he says, tossing the folded fabric onto your bed. “Yuzuriha. She insisted on something ‘birthday-appropriate’ and then asked me six times if it matched your demeanor. I still don’t know what she expected me to say.”
You pick it up. It’s soft. Well-made. Definitely not something you’d ever bother asking for.
“Meat,” Senku continues, hanging the bundles on a peg. “Cured. Tsukasa supervised. Taiju carried it and celebrated the entire time about how this was a proper ‘symbol of friendship.’”
“Was it?”
“Tch, no.” A small furrow creases his brow. “I didn’t feel like wasting brain cells explaining to that oaf that I’d already beaten him in the romance category.”
You snort.
“Flowers from our Dear little Suika,” he says, nodding at the slightly crushed bouquet now decorating your table. “She picked extras in case you ‘wanted options.’”
“Options for what?”
“She didn’t clarify.”
You glance at the picture tucked under his arm. “And that?”
He hands it over. “Minami. Sunrise over the ridge. Said it felt ‘honest.’ I didn’t argue.”
The scenery carries a quiet that creeps in slowly—soft lines, gentle shadows, light held just enough to matter. It’s the kind of photograph people in the old world would’ve obsessed over, valuable even unfinished, even colorless, simply because it caught something real.
“…Wow,” you mutter.
“Don’t get all mushy gushy yet,” Senku snaps immediately. “We’re not done.”
He reaches into his waistband pouch and throws out a bolt.
Then, a nut.
Then, he threw out a screw.
A screw diver.
Then another.
Then—unfortunately—another.
You point at the clutter. “Senku.”
“Hold on.”
“Senku.”
“Almost got it—”
“Why are there infinite pockets on your person.”
“Efficiency.”
”Efficiency MY ASS, you better clean up my floor before I step on something and puncture my foot.”
“Ah… here it is,” He mutters before finally straightening his posture, now holding up a necklace.
It’s simple, cleanly made. A smooth, polished stone hangs at the center—translucent, reddish-orange, catching the light in subtle bands.
You’ve never seen it before.
“This,” Senku says, tone shifting into lecture mode, “is nambulite.”
“Uhm,” You raise a brow. “Gesundheit?”
He ignores you. “It’s a rare mineral. Only forms under specific conditions. Chrome found trace indicators weeks ago and wouldn’t shut up about it. Took us forever to locate a viable deposit without destroying it.”
You turn the stone between your fingers. It’s warm.
“Kaseki did the metalwork,” Senku adds. “Complained the whole time about my ‘lack of sentimentality.’”
“Did you tell him you’re emotionally constipated?”
“Constantly.”
He steps closer to fasten it around your neck. His fingers are precise, familiar, careful without making a big deal of it.
“There,” he says. “Don’t lose it.”
You smirk. “Hm, I didn’t peg you as the type to assign sentimental value to a rock.”
“It’s not sentimental,” he replies. “It’s rare. Big difference.”
You meet his eyes. “You spent weeks on this.”
He shrugs. “Yeah, well. You occupy a lot of my thoughts, sue me.”
There’s a beat.
Then you break it by reaching for the knife beside the cake— In all honesty, its excessive layers nearly obscured the utensil.
“So,” you say, cutting into the cake, “are we eating now, or is there some unhinged science demonstration I should brace for?”
“No demo,” Senku says. “Just eat before Magma or Yo smell it and declares it a communal resource.”
You take a bite.
It’s absurdly good.
You pause. Chew. Swallow.
“…okay,” you admit. “That was illegal.”
“Told you,” he says, smug. “Ten billion percent worth the effort.”
You lean back against the table, surveying the mess—gifts, flowers, food, evidence of a village quietly conspiring without you noticing.
“…hey,” you say, quieter. “Thanks. Seriously.”
He waves it off. “Yeah, yeah. Don’t get sappy. I did this because if you were grumpy on your birthday, it’d throw off productivity.”
You smile anyway.
“Sure,” you say. “Keep telling yourself that.”
He snorts, reaching for his own slice of cake and taking a bite.
You two eat in silence for a bit. though, it doesn’t last long.
Senku clears his throat in an intentional, exaggerated way.
“Happy birthday,” He huffs, reaching out to ruffle your hair like it’s muscle memory. “C’mon. I’ll help you get ready—you can try the dress on.”
He pauses, plucks a flower from the bundle, turning it between his fingers with quiet focus. “Huh. Could stick one in your hair. Or preserve it.” A beat, then a crooked grin. “Not that it’s hard. I’d just have to teach you.”
He continues to fuss over the flowers, clearly on the verge of another unsolicited rant.
You slump back into the blankets, arms crossed. “You know… this is way too romantic for me. Totally overkill.”
Senku glances at your cake slice, shrugs, and slides it onto the table. “Whatever. You can dissect that later. Right now, you’re not staying in bed all day.”
“Excuse me? I’m conducting a very important sleep experiment,” you say, narrowing your eyes.
“Experiment fails,” he says flatly, reaching for your wrist. “Come on. Even the Stone World doesn’t run on extra rest periods.”
You resist—half-heartedly—and, on impulse, grab him by the front of his shirt, yanking him down onto the bed with you. “Not so fast, genius,” you mutter, letting your head rest against his chest.
Senku groans, a long, exaggerated sigh, but instead of pushing away, he settles, one arm draped lazily over you. “We don’t have time in the schedule to linger like this,” he says, voice brisk but softer now, like he’s forcing the words out scientifically.
Then, after a pause, “But… it’s your birthday. One day. Exception granted.”
You peek up at him, smirking. “An exception, huh? Didn’t know pragmatic scientists like you could bend the rules for… people.”
“Don’t get used to it,” he mutters, fingers brushing lightly through your hair. “One day. One exception. And that’s all you’re getting.”
You laugh, quiet and soft, and squeeze a little closer. “Thanks, Senku. Really.”
He lets out a little huff, like he’s annoyed, but it lacks any real bite. “Yeah, yeah. Don’t think you’re getting any other special privileges or pampering. This is it.”
But as he rests his chin lightly against your head, the way he stays, even with his signature smugness intact, tells you everything.