Han Taejin came out of the economics building with a notebook under one arm and his backpack hanging off one shoulder. The walkway ahead was clogged.
It usually was around noon.
Students drifted across the open stretch between buildings in loose groups, slowing down whenever they felt like it, stopping wherever it was least convenient, and somehow still looking surprised when someone bumped into them. A pair of first-years had stopped near the steps to argue over an assignment, both of them standing in the middle of the path like they'd paid rent on the concrete.
Taejin stepped around them without saying anything.
A hand shoved a flyer into his direction before he made it three more steps.
"Excuse me, are you interested in joining—"
"No."
The boy holding the flyers blinked. "You didn't even hear what it was."
Taejin kept walking. "That was enough."
Behind him, the boy made a quiet, offended sound and moved on to someone with weaker instincts.
It was the kind of ordinary campus interaction he usually forgot a minute later. That was why the sky bothered him more than it should have.
He only looked up because too many other people were already doing it.
There was a crowd beginning to form near the fountain plaza, not a real crowd yet, but the kind that could turn into one in under a minute. Half of them were staring upward. The other half were holding phones over their heads like whatever was happening would look more believable on a screen.
Taejin stopped just long enough to see what they were looking at.
The sky over the western side of the city looked strange.
There were clouds, but not the kind that meant rain. The light had changed instead. It had a pale metallic cast to it, making the tops of the buildings and the window glass look too bright. The blue behind the clouds seemed thinner than usual, as if something was pressing against it from above.
A girl near the fountain said, "Can you see that clearly?"
Her friend squinted at her phone. "It looks better on video."
"Of course it does," Taejin muttered, and started walking again.
He didn't know what it was. That didn't mean standing around in a growing crowd would help.
The air felt off too.
He noticed it halfway across the courtyard. Not because of temperature. The day wasn't especially hot or cold. It was the pressure. It felt as though the atmosphere had shifted without warning, like the campus had been sealed under a glass bowl while nobody was paying attention.
He rolled one shoulder under the weight of his bag and headed toward the convenience store beside the lecture hall.
A message from Kim Minwoo was waiting on his phone.
You eating before class?
Taejin typed back while walking.
Store first.
The reply came immediately.
If you see the tuna kimbap take two. People are already buying like war's about to start
Taejin glanced once more at the strange sky and slid the phone back into his pocket.
That would have been a stupid joke on any other day.
Inside the store, the fluorescent lights buzzed faintly overhead. The old cashier looked up from the register, then past Taejin, toward the glass doors.
"You saw outside?" he asked.
Taejin took two bottles of water from the cooler. Then he paused, thought about it, and took a third.
"Hard to miss."
"Feels weird."
Taejin added two triangle kimbap and a protein bar to the counter. "Then maybe you should pull the shutters."
The cashier gave him a look somewhere between amusement and irritation. "You always this pleasant?"
"Only around lunchtime."
The old man snorted, rang him up, and handed over the receipt. "If classes get canceled, don't all rush back in here at once. You people become animals around instant noodles."
"That's optimistic," Taejin said. "Animals are usually more organized."
He took the bag and pushed back out through the sliding doors.
The plaza outside had changed in the minute or two he'd been inside.
More people had gathered. A few professors were standing farther out now, talking to each other and looking up with the kind of forced composure adults put on when they wanted younger people to stop panicking before they'd had time to panic themselves.
A student in a film department hoodie was livestreaming.
Another guy had climbed onto the edge of the fountain for a better angle.
A cluster of girls near the humanities building were all looking down at their phones, then back up, then down again, as if waiting for one of the devices to explain the sky for them.
Taejin twisted open one of the waters and drank half of it.
Then he noticed the birds.
There were sparrows gathered near the curb by the vending machines and a pair of pigeons under one of the benches. They weren't pecking at food or hopping around in the usual nervous little bursts. They were just standing there.
Still.
He watched them for a second longer than he meant to.
Then every phone on the plaza buzzed at once.
The sound snapped across the courtyard hard enough to make several people jump. Conversations stopped. The guy on the fountain nearly dropped his phone. Someone let out a surprised laugh.
Taejin took his phone out.
The screen had gone black.
For a moment he thought it had shut down. Then a thin line of pale silver light appeared, but not on the screen itself. It hovered a little farther out, too sharp and too clear to be a reflection. He frowned and lifted his head.
The line unfolded into a narrow translucent pane floating in front of his vision.
A girl by the fountain gasped and slapped at the air in front of her face. Her hand passed straight through it.
"What the hell?"
More panes appeared around the plaza, not physically hanging in the air, but fixed in each person's line of sight. Everyone was looking at slightly different angles, but reacting to the same thing.
Words formed across Taejin's pane in clean silver text.
[Assimilation Support System Activated]
No one moved for a second.
Then the whole plaza erupted.
"What is that?"
"Can everybody see this?"
"It's not on my phone!"
"How do I get rid of it?"
A professor raised his voice over the noise. "Everyone calm down. Do not start running. We don't know what this is yet."
Nobody calmed down.
The text on Taejin's interface shifted.
[Earth Mana Induction Detected]
[Assimilation will begin shortly]
Mana.
The word alone was enough to make several people laugh in disbelief.
"That's fake."
"There's no way that says mana."
"Is this some kind of school event?"
"Since when does the school have a budget for this?"
"It has to be AR."
"Then why can't I turn it off?"
One of the boys near the fountain waved both arms through the interface, then looked around as if waiting for someone to admit they'd hidden cameras everywhere.
Taejin didn't bother trying that much. He moved one hand across his line of sight once, confirmed the pane wasn't physical, then looked around the plaza instead.
Everyone could see it.
That mattered more than the exact wording did.
The old explanations were already losing ground. Prank, malfunction, app, AR— those only worked if the phenomenon stayed contained. This hadn't. The whole campus was reacting at once. Probably more than the campus.
The pressure in the air had gotten stronger, or maybe he was just noticing it more now. His skin felt a little too awake, as if the surface of his body had started paying attention to something before the rest of him caught up.
A new line appeared.
[Purpose: assist host adaptation to mana environment]
Taejin stared at it for a second.
Assist host adaptation.
That was the sort of sentence you either ignored immediately or took very seriously.
People around him chose the first option.
"This is insane."
"I'm calling my mom."
"No, wait, don't leave—"
"Why shouldn't we leave?"
The same professor was still trying to keep things together. "Please remain in your current area until we receive guidance from the administration."
Someone in the crowd said, "You don't know what this is either!"
The professor's mouth tightened. "That's why I'm telling you not to panic."
Taejin looked at the number that had appeared at the bottom of the pane.
[00:28:13]
A countdown.
That was enough to make him change his plans.
He stepped away from the growing crowd and toward the building line where there were fewer people packed together. If something was going to happen in twenty-eight minutes, then being shoulder to shoulder with a hundred panicking students at the center of campus was one of the worst places to be.
His phone buzzed again, though the black screen remained useless.
Minwoo.
What the hell is this?
Another message came immediately after.
Everyone in the student center is freaking out
Taejin typed while walking.
Leave the student center. Too crowded.
Three dots appeared. Then:
You serious?
Taejin looked once at the translucent pane, then at the crowd by the fountain, which was somehow thicker now than it had been thirty seconds ago.
Yes. Somewhere smaller. Less people.
He sent it and put the phone away.
That was the point where he stopped treating the event as bizarre and started treating it as dangerous.
People didn't need to understand something perfectly for it to kill them. The countdown alone was enough reason to move.
He headed down the side path beside the social sciences building, away from the main plaza and toward the science wing.
The clinic would be everyone's first thought. That made it a terrible option. Same for the student center, the library lobby, or any large hall where a lot of people could gather and wait for announcements.
The pharmacy building was better.
It had supplies, smaller rooms, and fewer random people passing through. If the interface's warning about "adaptation" meant anything physical, then water, barriers, and a door he could lock mattered more than being near whoever shouted instructions the loudest.
The campus speakers crackled overhead.
"This is the administrative office. All students are advised to remain calm and proceed in an orderly manner to—"
Static swallowed the rest.
A second later the voice came back, thinner and more strained.
"—please do not rush—"
Then silence.
Taejin kept walking.
He passed a row of benches under the trees between buildings and noticed that the birds had moved. Or rather, some of them hadn't. One pigeon was still under a bench, but now it had sunk low against the concrete, feathers twitching once every few seconds.
A pair of students were staring at it from several steps back.
"Was it like that before?"
"I don't know."
"Should we call someone?"
"For a bird?"
Taejin didn't stop.
Two girls in nursing department jackets hurried past him in the opposite direction, one of them saying, "My dad says to get off campus."
"How? Look at the roads."
A guy farther up the path was trying to joke his way through panic. "If this is the apocalypse, I'm failing the tutorial."
Nobody laughed.
The interface updated again.
[Remain calm]
[Panic increases failure risk]
Then, a few seconds later:
[Failure to adapt may result in biological collapse, corruption, or loss of self]
That changed the mood.
Even people who had been laughing before went quiet after that one.
Taejin slowed near the low wall by the science courtyard and read the line again.
Biological collapse.
Corruption.
Loss of self.
The wording was vague, but not in a harmless way. Whatever this "assimilation" was, failure didn't sound like fainting. It sounded permanent.
That meant crowds had become worse than useless.
He looked around the courtyard and took stock automatically.
Open space in the middle. Too exposed.
Main science entrance ahead. Too obvious.
Side access corridor by the prep rooms. Better.
Emergency stairwell on the east side if needed later.
A student near the courtyard doors was crying into her phone.
"They aren't answering. Nobody's answering."
Another one snapped, "Then stop calling and think."
Not a bad idea. Too late to help her.
Taejin checked the countdown again.
[00:23:41]
Not enough time to waste.
He headed for the side entrance to the pharmacy building.
His phone buzzed.
Minwoo again.
Where are you going?
Pharmacy building.
A pause.
Why there?
Taejin typed back with one thumb.
Less crowded. Better rooms. Supplies.
The reply came slower this time.
You really think this is real
Taejin looked up.
A man in a maintenance uniform had come out from between two buildings carrying a toolbox. He stopped halfway across the path and stared at the interface hanging in front of his face, then at the sky, then at the students moving around him like they were all trying to solve the same problem from different directions.
None of them looked like they knew what to do.
Taejin sent the message.
I think waiting around people who don't know what to do is worse.
He slid the phone away.
That was the truth of it. He didn't know exactly what the interface was either. But he knew enough to recognize bad conditions before they got worse.
The pharmacy side entrance was unlocked.
Inside, the air-conditioning hit him first, then the smell of paper, disinfectant, and stale fluorescent light. The building still looked normal, which somehow made the interface floating in front of his eyes feel more unsettling.
A few students stood in the lobby, talking too loudly. Two professors were trying to keep their voices low and failing. Someone near the wall kept swiping a hand through the interface every few seconds as if brute force might eventually solve the problem.
Taejin moved past them without stopping.
The prep corridor deeper in the building was quieter.
Good.
He didn't need silence. He needed fewer bodies.
As he walked, he paid attention to the details that mattered: room sizes, side doors, stairwell access, emergency signs, supply carts left in the hall, places where a crowd could jam up if they all ran at once. He didn't think of it as strategy. It was simpler than that.
If something went wrong, where would everyone run?
Where would they get trapped?
Where would he not want to be standing when they did?
A cabinet door slammed somewhere farther down the hall.
Then footsteps. Fast, uneven.
A pharmacy student he vaguely recognized from general ed classes came around the corner carrying a plastic crate full of bottled water and medical tape. Her face was pale.
Taejin stepped aside to let her pass.
She looked at him as she went by and said, "You should grab supplies now."
"Working on it."
She gave a short, humorless nod and kept moving.
Useful information. Better than the crowd outside.
He checked the countdown again.
[00:21:02]
Then, for the first time, he felt something under his skin that wasn't just nerves.
A faint tightness spread through his arms and chest, subtle enough that he might have ignored it if he hadn't already been paying attention. It wasn't pain. It felt more like pressure moving in places pressure shouldn't be, as though his body had become aware of itself in the wrong way.
He stopped walking.
The sensation passed after a few seconds, leaving behind a thin unease he didn't like at all.
So it had started early for some people.
Or maybe it had started for everyone and most of them hadn't noticed yet.
Either way, the warning about biology had just become harder to dismiss.
Taejin turned into a partially open storage room near the end of the prep corridor. Inside were shelves of packaged gloves, distilled water, cleaning alcohol, tape, sealed boxes of lab supplies, and other things that might or might not matter depending on how bad the next hour became.
He took:
two more water bottles,
a roll of tape,
scissors,
gloves,
and a small bottle of sanitizer.
Not because he had a full plan. Because those were useful things and they were here now.
His phone buzzed one last time.
bro someone just passed out in the student center
Taejin went still.
The message was followed by another before he could answer.
Wait no maybe two
Then:
What do I do
A shout rang out somewhere deeper in the building.
Not words at first. Just shock.
Then a voice, louder and much closer than before:
"Hey—hey, are you okay?"
Another voice answered from the hall outside the storage room.
"What happened?"
"I don't know, she just—"
Something hit the floor.
Hard.
The interface in front of Taejin's eyes pulsed once, brighter than before.
[Assimilation begins in 00:19:37]
He looked toward the half-open storage room door.
Outside, hurried footsteps were converging on the corridor. Somebody was breathing too fast. Another person said, "Call the clinic."
A third voice snapped back, "They're not answering."
Taejin zipped his bag, picked it up, and stepped toward the door.
The first student he saw in the hallway was down on one knee beside a girl who had collapsed against the wall. Blood was running from one of her nostrils. Her hand twitched once on the tile.
The students around her had no idea what to do.
That was obvious from how close they stood.
Too close. Talking over each other. Looking for someone else to decide.
Taejin took in the scene for one second and understood the only part that mattered.
The crowd was about to become the problem.
He turned away from them and headed deeper into the building.