It started with a lab accident.

Nothing dramatic—just a beaker that cracked under heat stress and a puff of smoke that sent you coughing into your sleeve. Senku rushed over, eyes sharp, hands steady, already muttering about thermal coefficients and glass fatigue.

“You okay?” he asked, voice clipped.

You nodded, waving the smoke away. “Just startled.”

He frowned, inspecting the broken glass like it had personally offended him. “Shouldn’t have happened. I calculated the tolerance.”

You leaned against the counter, watching him work. “Maybe the beaker didn’t get the memo.”

He snorted. “Glass doesn’t read memos. It breaks.”

You smiled. “So do people.”

That made him pause.

He looked at you then—really looked. Not like a variable, not like a data point. Like someone he couldn’t quite solve.

“You’re not glass,” he said finally. “You’re… more stable.”

You raised an eyebrow. “Stable?”

He flushed slightly, turning back to the mess. “I mean emotionally. You don’t panic. You adapt.”

You stepped closer, brushing a shard into the trash. “And you? What are you made of?”

He hesitated. “Carbon. Mostly. Like everyone else.”

You laughed. “That’s not what I meant.”

He didn’t answer right away. Just stared at the counter, then at you, then back again.

“I’m made of reactions,” he said quietly. “Fast ones. Controlled ones. Sometimes… unpredictable.”

You reached for his hand, fingers brushing his wrist. “Then maybe we’re both experiments.”

He looked down at your touch, then up at your face. “If this is an experiment,” he said, “I don’t want it to end.”

And in that quiet lab, with the world still whole and the future still unwritten, Senku Ishigami let himself feel something he couldn’t measure.

Something warm.

Something human.