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English
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Part 1 of Chasing Yesterday
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Published:
2026-07-10
Updated:
2026-08-06
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20/?
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Chasing Yesterday - When the Past Wakes in the Future

Summary:

"You're legally a mess."
"Thanks."
"We'll fix it."

Oboro Shirakumo was supposed to die.
Instead, he wakes up fifteen years in the future.

The world survived a war. His classmates became heroes. His best friend became Eraser Head, a teacher, a husband... and somehow the father of two kids who insist on making room for him at the dinner table.

Oboro was only gone for a moment.
The world kept moving without him.

Or: A story about grief, found family, rebuilding a life after losing everything, an adopted brother who quietly becomes indispensable, two exhausted dads doing their best, and one green-haired hero student might just convince him that the future still has something worth looking forward to.

Chapter 1: Fifteen Seconds

Notes:

(See the end of the chapter for notes.)

Chapter Text

Cold settled somewhere deep beneath his skin until he couldn't remember if he'd ever been warm to begin with.

Breathing came hard, every shallow inhale catching in his chest before it could fill his lungs. Something pressed against him—not enough to hurt, not anymore—but enough that drawing another breath felt like asking too much of a body that had already decided it was finished.

There was a taste in his mouth.

The taste of dust lingered on his tongue, chased by something metallic and bitter that refused to leave the back of his throat.

His ears rang.

At first he thought it was silence.

Gradually, other sounds began to surface beneath the endless high-pitched whine.

A low groan rumbled in his chest.

The distant crack of something giving way.

'Water'.

Or maybe rain.

He couldn't tell.

His thoughts drifted in and out without ever quite settling. Every time he reached for one, it dissolved before he could make sense of it.

He tried to remember where he was.

Nothing.

He tried to remember why his chest hurt.

Nothing.

...

'Sho?'

The thought surfaced suddenly, as instinctive as drawing breath.

'Where's Sho?'

He'd been...

...

'I was with Sho.'

A sharp pressure bloomed behind his eyes before the thought slipped away again, dissolving into the ringing in his ears before he could hold onto it.

He tried to open his eyes, but they wouldn't listen.

For a long moment, there was only darkness and the strange sensation of floating somewhere between waking and sleep.

Then—

A voice.

Faint.

Far away.

It slipped through the ringing in his ears, too distorted to understand, swallowed almost immediately by another deep, shuddering groan that seemed to come from the earth itself.

The sound faded.

The voice came again.

Closer.

Urgent.

He frowned.

Someone was calling.

He knew that voice.

Didn't he?

Another crack echoed somewhere overhead.

Instinctively, his body tensed.

He didn't know why.

The voice broke through the ringing one last time.

"...ro!"

Not a word.

Just a fragment.

Just enough to make something twist painfully in his chest.

A name rose to his lips before he even knew he was speaking. "...Sho?"

The whisper barely existed, carried away almost as soon as it left him.

Something was wrong.

He should...

He needed to—U.A.

The thought surfaced with startling clarity.

'Need to get back...'

'Sho's there.'

It felt important.

Urgent.

He couldn't remember why.

Before he could reach for the thought, it slipped away again, disappearing beneath the relentless ringing in his ears.

The cold remained.

His body lurched as though the ground had vanished beneath him, and for one impossible heartbeat he felt suspended in empty space.

A sharp breath tore itself from his lungs.

His eyes flew open.

Gray.

Gray sky stretched endlessly above him, blurred around the edges as though someone had smeared charcoal across the world.

He blinked against the light, his heart hammering for reasons he couldn't explain.

His body ached.

His head throbbed.

His clothes were damp.

For several long seconds, all he could do was lie there, staring upward, trying to remember why waking up felt so much harder than it should have.

He came up with nothing.

He blinked.

"...What..."

His own voice sounded wrong—rough, cracked from disuse.

He pushed himself upright.

Every muscle protested.

A sharp pain lanced through his shoulder, followed by another across his ribs.

"...Ow."

He sat still until the world stopped spinning.

'Where...'

'Where am I?'

His memory felt slippery.

'Training.'

'No...'

...

'Work study.'

A cool drop landed against his cheek, making him flinch.

Another.

Then another.

'Rain?'

Slowly, he lifted a trembling hand and brushed his fingers across his face. The skin there was damp, the droplets cool against his fingertips. He stared at the moisture for a long moment, watching it bead on the back of his hand before another drop splashed softly against his wrist.

His gaze drifted upward.

The sky stretched overhead in a blanket of soft gray, thick clouds hanging low enough that they seemed almost within reach. There was no downpour, only a gentle drizzle that whispered against the earth, quiet enough that he hadn't noticed it until now.

He drew in a careful breath.

The air smelled of wet soil and fresh rain.

Clean.

Too clean.

Not dust.

Not smoke.

Not...

Something about that felt wrong.

His brow furrowed.

He couldn't explain why.

Another raindrop slid from his temple to his jaw, cold enough to send a faint shiver through him.

He wiped it away absently and looked around for the first time.

Nothing looked familiar.

'There'd been shouting.'

'A building...'

'Trapped'—His stomach twisted.

He remembered running.

Then...Nothing.

"Hi there."

A voice drifted toward him through the rain, warm and unmistakably real, cutting through the haze that still wrapped itself around his thoughts.

"What're you doing lying on the ground?"

He flinched, instinctively twisting toward the sound far faster than his battered body was prepared for, and immediately regretted it as pain shot through the side of his neck and settled behind his eyes. "Ngh..."

The world lurched violently.

The horizon tilted, the gray sky and rain-dark grass blurring together into an indistinguishable smear as a wave of dizziness rolled over him hard enough to steal the breath from his lungs. He barely registered himself pitching sideways before a pair of steady hands caught him beneath the shoulders, stopping him from collapsing back into the soaked earth.

"Woah there, easy, kid."

The stranger's grip was firm but careful, keeping most of his weight without forcing him upright.

"You alright?"

He wanted to answer.

Instead, a violent cough tore through him, each rasping breath leaving his chest feeling heavier than the last, as though every inhale had to fight against something lodged deep inside his lungs. By the time it subsided, he was left breathing shallowly, one hand pressed instinctively against his ribs.

'Where...'

'Where was he?'

The question drifted through his mind without an answer.

His eyes wandered over the damp grass beneath his feet, the rain continuing to fall in a soft, persistent drizzle that soaked quietly into the ground instead of pounding against it. The light had faded to a deep blue-gray, the kind that settled over the world just before nightfall.

'When had it gotten so late?'

He frowned.

'Hadn't it just been...'

His thoughts slipped away before he could finish them.

Looking down at himself, he stared blankly at the state of his costume.

His hero uniform was caked in dirt and concrete dust, one glove torn nearly to the wrist, streaks of dried blood dark against the sleeve where the rain hadn't yet washed them away.

For several long moments, he simply stared.

"...Great."

The word escaped on a tired breath.

Akane's gonna kill me.

The stranger let out a quiet sigh that almost sounded amused.

The man shifted his grip slightly, making sure he was steady before speaking again.

"Come on. Let's get you somewhere warm and have someone take a look at you."

There was a brief pause. "Do you know where you are?"

The question felt oddly difficult to answer.

He searched his surroundings again, as though the trees and unfamiliar buildings might suddenly provide an explanation, but everything felt just...slightly wrong.

Slowly, he shook his head.

His throat felt painfully dry. "W-where..."

The word caught halfway out.

He swallowed, trying again.

"What... happened?"

For just a moment, the stranger didn't answer.

Then, in a voice so calm it almost sounded reassuring, he said,

"You're at U.A., kid."

The words settled somewhere deep inside him.

'U.A.'

His shoulders loosened almost imperceptibly.

He didn't understand why he was there.

He didn't remember coming back.

He couldn't even remember leaving.

But hearing those two letters eased something tight inside his chest all the same, and without thinking, he leaned ever so slightly into the stranger's steady support as they began walking toward the lights waiting beyond the rain.

 


 

The gates of U.A. stood exactly where he remembered.

Mostly.

Something had changed.

The walls were taller.

There were more security checkpoints than he remembered, reinforced steel replacing the old fencing, while construction equipment sat idle nearby as though someone had simply walked away for the evening.

'Had they renovated?'

He frowned, trying to remember if there had been plans for an expansion.

Nothing came to mind.

They approached the front entrance at an unhurried pace, the stranger never once removing the steady arm wrapped around his shoulders. Every few steps the world threatened to tilt again, and each time the man's grip tightened just enough to keep him upright without making him feel restrained.

"Easy," he murmured. "No rush."

For the first time since waking, he found himself properly looking at the man beside him.

He wore a long dark coat over a hero costume, his face obscured by a mask that left only sharp, observant eyes visible beneath the brim of a familiar hat.

Something stirred at the edge of his memory.

Those eyes...

That hat…

'...Snipe-sensei?'

The thought appeared so suddenly it caught him off guard.

'No...'

That couldn't be right.

Why would Snipe-sensei be—His head throbbed.

The thought slipped away before he could catch it, dissolving into the same fog that seemed determined to swallow every memory he reached for.

The stranger continued speaking as they walked, his voice calm and conversational, though the words drifted in and out of focus.

"...probably hit your head..."

"...don't worry..."

"...someone will know what to do..."

He caught only fragments.

The campus itself barely looked like the one he remembered. The familiar paths remained, but newer buildings stood where open courtyards should have been, while others had disappeared altogether beneath scaffolding and temporary barriers. Even the trees seemed taller, their branches stretching farther overhead than he remembered.

It felt like walking through a dream built from pieces of home.

Everything was recognizable.

Nothing was quite right.

"...Where are we going?" The question escaped before he realized he'd spoken.

The stranger glanced over.

"The principal's office."

He adjusted his grip as they climbed the shallow steps toward the main building.

"Campus is pretty deserted this time of year. We'll get you somewhere warm, and Principal Nezu can call Recovery Girl to have you looked over."

'Recovery Girl.'

The name settled comfortably in his mind.

He gave a small, absent nod.

"Okay."

If Recovery Girl was there...

Then everything would be fine.

Wouldn't it?

The remainder of the walk passed in a quiet blur.

His surroundings drifted in and out of focus, familiar landmarks appearing only to dissolve into something subtly different before he could make sense of them. Buildings seemed taller than he remembered. Pathways curved where he could have sworn they had once run straight. Even the trees looked older, their branches stretching farther overhead until they formed a canopy that swallowed the fading evening light.

He couldn't shake the feeling that he had been here before.

And yet...

He couldn't remember this place looking quite like this.

Eventually, they stopped.

The stranger raised a gloved hand and knocked twice against a heavy wooden door.

"Come in."

The voice from within was calm and measured, carrying the quiet confidence he remembered so well.

The stranger slid the door open before helping him over the threshold.

"Good evening, sir."

"Good evening, Snipe."

The room smelled faintly of tea and old books.

Stacks of paperwork covered the large desk near the windows, though the small figure seated behind it looked up immediately, bright eyes flicking from Snipe to the boy leaning heavily against his shoulder.

For a brief moment, the room was perfectly still.

The principal's pleasant smile remained exactly where it was.

Only his eyes changed.

"I see you've brought me a guest."

"Found him unconscious on campus," Snipe explained, carefully easing the boy into one of the chairs opposite the desk. "Looks like he's taken a pretty nasty hit to the head. He's disoriented and doesn't seem to remember how he got here. I figured Recovery Girl should take a look before we ask too many questions."

"A wise decision."

The principal climbed down from his chair with surprising agility and padded around the desk, stopping only a few feet away.

His expression remained warm, though there was a quiet curiosity in his eyes, the kind of careful observation that made the boy feel as though he were being understood long before a single question had been asked.

The boy looked up at him, relief flickering briefly across his face.

"Principal Nezu..."

The principal tilted his head ever so slightly.

"You know me?"

"...Of course."

The answer came automatically.

'Didn't everyone know Principal Nezu?'

Something about the question felt strange.

He frowned.

Before he could think on it further, another realization struck him.

The stranger.

The voice.

The hat.

The mask.

His head snapped toward the man beside him.

"...Snipe-sensei?"

Snipe blinked.

"...Yes?"

The boy's brow furrowed.

"Do..." His voice caught. "...Do you know me?"

Silence settled over the office.

Snipe searched his face carefully, his eyes narrowing ever so slightly as though trying to place a half-forgotten memory.

After several long seconds, he slowly shook his head.

"I'm sorry, kid."

The words landed far heavier than they should have.

Something inside him lurched.

'That wasn't right.'

'It couldn't be.'

'He knew Snipe.'

'Didn't he?'

His pulse quickened.

The room suddenly felt too warm.

His breathing became shallow.

"What..."

He looked from Snipe to Nezu and back again, desperately searching their faces for something that made sense.

"What's going on?"

Neither of them answered immediately.

Instead, Nezu regarded him with quiet patience, his gaze never wavering.

Finally, he spoke.

"May I ask your name?"

The question should have been simple.

Instead, his mind went blank.

He opened his mouth.

Nothing came out.

His own name seemed impossibly far away, hidden somewhere just beyond his reach.

"...I..."

He swallowed hard.

"...I'm..."

The answer surfaced almost reluctantly.

"...Oboro."

His voice was barely above a whisper.

"...Oboro Shirakumo."

The silence that followed felt deafening.

Snipe's expression drained of all color.

His eyes widened as realization crashed over him in an instant, every odd detail suddenly falling into place—the outdated uniform, the familiar smile, the face that hadn't aged a single day.

"No..."

The word escaped before he could stop it.

His gaze remained fixed on the boy.

"That's..."

He shook his head once, slowly, as though trying to wake himself from a dream.

"That's impossible."

The office fell quiet once more.

Finally, Snipe looked toward Nezu, his voice little more than a disbelieving whisper.

"Shirakumo is dead."

Nezu's expression remained as composed as ever, though there was a gravity behind his eyes that hadn't been there moments before.

"Yes," he said softly. "He is."

His gaze returned to the bewildered teenager standing before him.

"And yet..."

A small, thoughtful smile crossed his face.

"...here he is."

Oboro looked from Snipe to Principal Nezu, searching both their faces for the answer that neither seemed willing—or able—to give him.

It didn't make sense.

One moment he had been running.

Sho had been shouting.

The world had come apart beneath his feet.

And then...He had opened his eyes in the rain.

It couldn't have been more than fifteen seconds.



Notes:

Thanks so much for reading! I'd love to know what you thought of Oboro's introduction to this very unfamiliar version of U.A.

Also... be honest.

What was your favorite line?
When did you first realize something was seriously wrong?
Where do you think the story goes from here?
And if you were Oboro, what would be the very first question you'd ask?