The Longest Twenty-Four Hours
Summary: reader is hit by a villain’s regression Quirk, transforming her into her curious six-year-old self, forcing Todoroki to survive a day of babysitting.
Shouto stepped over the collapsed concrete, scanning the abandoned warehouse for any lingering civilians. The villain they’d been pursuing was already restrained, wrapped in ice up to his shoulders.
“You okay?” he called over his shoulder.
He turned just in time to see a flash of pale gold light explode behind you, catching you off guard.
The quirk slammed into you before he could raise an ice wall. Your body shimmered, shrinking so quickly that your hero costume crumpled into a heap on the broken floor.
Where you had been standing moments ago…
A little girl sat in the middle of your clothes. She couldn’t have been older than six.
She blinked up at him with watery eyes, clutching the oversized sleeve of your costume around herself like a blanket.
You sat wrapped in one of his spare jackets, your tiny legs dangling off the examination bed while doctors ran scan after scan.
He stood outside the room, replaying those few seconds over and over. He looked away for one second, that’s all it took.
The doctor eventually stepped outside. “The quirk appears to be temporary.”
Shouto looked up relieved. “How long?”
“Maximum twenty-four hours. Physically and mentally she’s regressed to approximately six years old.”
The doctor nodded sympathetically. “She won’t remember ever being an adult until the quirk wears off. Treat her like any other child her age. Keep her supervised, avoid dangerous situations, and bring her back if anything changes.”
Shouto stared at the floor. “…This happened because I wasn’t paying attention.”
The doctor touched his shoulder sympathetically, “Don’t blame yourself, at least she’s not hurt.”
“You live here?” Your eyes grew impossibly wide as you stepped into the apartment.
Shouto looked around. There wasn’t much to be excited about. Although it was your apartment too; you hadn’t remembered you did most of the decorating.
“You have the comfiest couch!” you declared proudly.
“You choose it,” he says instinctively.
“Huh? Really!” You nodded as though this made perfect sense. “That’s why it’s awesome.”
Then your stomach growled loudly, which caused you to dramatically collapsed onto the floor.
Shouto immediately knelt beside you. “Are you hurt?”
“My tummy is eating itself! Because I’m soooo hungry.”
“Oh.” He stood so quickly he nearly slipped.
Think, he told himself. What did six-year-old you eat? He scanned the fridge and the freezer.
He randomly remembered a conversation from months ago.
“There was a point in my childhood where I only ate chicken nuggets. My parents gave up trying to fight me.”
He shoved a tray into the oven, read the instructions three times just to make sure, and waited.
The apartment was suspiciously quiet.
“… you okay? Where are you hiding?”
He walked into the living room and the bathroom. Empty.
Panic set in immediately.
A tiny giggle echoed from his office.
He opened the door to find you had somehow climbed into his display cabinet.
His carefully organized hero figurines were scattered everywhere.
“No, no, no—” He rushed over just as you held up two collectible figures.
“Now kiss!”The figurines bumped together repeatedly.
One of them was All Might. The other… Endeavor.
“…Why are they kissing?” You nodded with complete confidence.
“They’re in love. People who love each other kiss,” you said matter of factly.
Shouto had absolutely no response to that. “…Please don’t make them kiss.”
“…Because they’re rivals.”
You considered that. “…Okay.”
Then you picked up Hawks and Endeavor instead. “These ones are married now.”
The nuggets eventually solved most of his problems.
You sat at the table swinging your legs happily while eating dinosaur-shaped chicken nuggets with enough ketchup to qualify as soup.
“It looks like a blob to me.”
You gasped pretending to be offended. You were such a funny child.
“You’re the best cook ever.”
Shouto looked at the overcooked nuggets.
No one had ever complimented his cooking before. “…Thank you.”
Keeping track of you turned out to be impossible.
Every cabinet had to be inspected. Every drawer had to be opened. Every blanket had to become a fort.
Every question had to be answered.
“Why is the microwave loud?”
“Like ocean waves?” This question was followed by you demonstrating what waves feel like at the beach.
“Why is your left eye look like that?”
“What do they taste like?”
“They’re not for tasting.”
“No.” This made Shouto realize that saying no to a child, made them even more curious.
By evening, Shouto was exhausted and somehow you still had plenty of energy.
“Can we play hide and seek?”
“I’m not very good at games.”
Before he could answer, you had already disappeared.
He searched the apartment and couldn’t find you at all.
“Come out, come out wherever you are,” he said, hoping you’d reveal yourself.
He checked behind the couch, under the bed, the bathroom.
Until he heard a tiny sneeze came from the hallway closet.
You grinned triumphantly from beneath a pile of blankets.
“I don’t think that’s how the game works,” he said chuckling.
Around bedtime, your energy finally disappeared.
You rubbed your eyes, hugging a pillow almost as big as you were.
You climbed onto the bed before suddenly looking nervous. “…Will you still be here when I wake up?”
The question caught him off guard; your small hands clutched the blanket. “I don’t wanna be alone.”
Shouto’s chest tightened. He remembered how frightened you’d looked after the quirk hit you. How everything familiar had suddenly become confusing.
He pulled a chair beside the bed. “I’ll stay.”
Within minutes, you were asleep.
Shouto sat quietly beside the bed, watching your tiny chest rise and fall with each peaceful breath. He couldn’t help but think you were the cutest child to ever exist. A small smile tugged at his lips.
He found himself wondering what it would have been like if the two of you had met as children instead. Your boundless curiosity and chaotic energy would have filled the silence that surrounded his own childhood. Maybe, just maybe, you would have convinced him that it was okay to laugh a little louder, ask a few more questions, and simply be a kid.
The thought warmed his heart… and hurt it at the same time.
He still blamed himself. He probably would for a long time. Tomorrow, though, everything would be back to normal. The quirk would wear off, and you’d wake up as your usual self again.
He could already imagine the look on your face when he told you everything you’d done today. A quiet chuckle escaped him.
He gently brushed a stray strand of hair away from your face before getting up to get ready for bed.
Dividers by: @designlikenonsense
