In Theory [Senku x Reader]

0.5 | The Familiarity of Snow

"More like built difficult."

For a moment, there was only the sound of your footsteps, rhythmic and steady against the packed snow.

A pause.

And then—

"...So, do you want to know wh—"

Your foot collided with his shin before he could finish.

Later, of course, you would learn the simple science behind it—how body heat disrupted the delicate lattice structure of ice crystals, melting them into water upon contact.

At the time, though, kicking Senku was far more satisfying.

You exhaled slowly, watching as your breath curled into the air, dissipating into the pale winter sky.

Tilting your head upward, you observed the snowfall once more. It resembled the memory lodged in the depths of your mind—flakes drifting in that same lazy, hypnotic descent—yet somehow, it felt heavier now. Perhaps that was natural.

You had never seen this much snow in Japan before.

Your gaze swept over the blanketed world around you, the silence pressing in with an almost eerie finality. A phenomenon worthy of a world record, you mused, though the thought felt strangely irrelevant. Time had long since abandoned its steady, predictable march. In a world overturned by centuries, records hardly seemed to matter anymore.

And in the Stone World, snow wasn't just an inconvenience—it was a threat.

No central heating, no flick of a switch to summon warmth, no thick down coats with insulated lining. Only crude fur-lined cloaks, layered fabrics, and the bitter struggle to keep fires burning against the relentless wind.

Winter stifled everything beneath its weight, slowing the rhythm of daily survival to a crawl. With the rivers frozen and the forests barren, the tasks you, Senku, and Taiju occupied yourselves with dwindled, leaving behind an excess of time and too little to fill it.

Taiju was out attempting to ice-fish—a noble effort, if not a particularly fruitful one—while Senku crouched over a clay pot, meticulously monitoring it to prevent another catastrophic explosion.

You caught yourself smiling at the memory of the last one.

As frustrating as it had been at the time, the sight of both Senku and Taiju drenched in half-fermented grape juice—an experiment in primitive winemaking gone terribly wrong—was something you wished you had immortalized on camera. The kind of blackmail material you would have treasured for years, stored away in an album, waiting for the perfect moment to unveil.

Rising from your spot, you made your way toward the pile of firewood you and Taiju had gathered that morning. Scooping up a few logs, you tossed them into the fire, ensuring the flames remained steady—the only thing standing between the three of you and the lethal cold.

Dying of hypothermia wasn't on your agenda.

Then again, there were worse ways to go.

And if history was anything to go by, your health had never been in your favor.

"How's the ancient Mesopotamian circa 3000 B.C. distillation method working out for you?"

Your voice cuts through the cold, your breath curling in the frigid air as you peer over Senku's hunched form.

"Just great." His tone is bone-dry, but his focus never wavers from the clay pot simmering over the fire. A thin trail of steam rises, curling like ghostly fingers into the morning air.