The first thing Lin Xia remembered was not Shen Lin's face.
It was the sound.
Mahjong tiles clicking against one another.
One.
Two.
Three.
A pause.
Then four tiles sliding across a wooden table.
She opened her eyes.
The ceiling of the dormitory room stared back at her.
For several seconds, she didn't move.
The sound had stopped.
Lin Xia slowly sat up.
Her heart was beating too quickly.
She looked toward the desk.
Nothing.
Her laptop was closed.
Her books were where she had left them.
The small lamp beside her bed was still switched off.
Everything looked normal.
But she could still hear the tiles.
Not in the room.
Inside her head.
She pressed both hands against her temples.
"Shen Lin..."
The name escaped before she could stop it.
She froze.
She hadn't meant to say it.
And that frightened her more than the memory itself.
Because yesterday, she had remembered him.
Today, she remembered something else.
A room.
A table.
Three students.
And a fourth chair that had always been empty.
Lin Xia climbed out of bed.
She went to her desk.
The Mahjong tile from yesterday was still there.
She had left it beside her laptop.
She picked it up.
The black symbol on its surface seemed darker than before.
A circle.
A vertical line through the center.
The same symbol from Bai Shuying's cheating device.
The same symbol from Room 318.
The same symbol appearing throughout the strange parts of XO Project.
Lin Xia turned the tile over.
There was writing on the back.
She hadn't noticed it yesterday.
Three tiny characters.
玩家十八
Player eighteen.
Her fingers tightened.
Then her laptop turned on.
She dropped the tile.
The screen remained black for two seconds.
Then white text appeared.
PLAYER 18
MEMORY RECOVERY: 8%
Lin Xia stared.
Another line appeared.
PREVIOUS SESSION DETECTED.
Then:
RESUME?
She didn't touch the keyboard.
The cursor moved by itself.
YES
The screen went black.
Lin Xia stepped backward.
"No."
The computer remained silent.
Then the final line appeared.
YOU ALREADY DID.
By eight-thirty, the four girls were sitting in an unused study room.
Yue Ning had brought three notebooks.
Mei Chen had brought two laptops.
Bai Shuying had brought her old notebook.
Lin Xia had brought the Mahjong tile.
Nobody had brought food.
Nobody was hungry.
Yue closed the door.
"Phones."
Mei raised an eyebrow.
"Why?"
"Because if the system is monitoring our devices, I don't want it hearing us through the microphones."
Mei stared at her.
Then slowly placed her phone on the table.
"That's paranoid."
"Yes."
Yue placed hers beside it.
"Good."
Bai followed.
Lin Xia hesitated.
Then placed hers down too.
Yue looked at the four devices.
"Now."
She pulled out a sheet of paper.
"Let's establish what we actually know."
Mei opened her laptop.
"Not what we think."
"Exactly."
Yue wrote the first heading.
FACTS
She looked at Lin Xia.
"One. Player 18 exists."
Lin Xia nodded.
"Two. The account was active three years ago."
"Three years and two months," Mei corrected.
Yue wrote it down.
"Three. The account belongs to Lin Xia."
Bai interrupted.
"Or it belonged to someone using her identity."
Lin Xia looked at her.
"That's possible."
Yue nodded.
"Four. Project X existed before XO Project."
Mei added:
"At this university."
"Five. Three students worked on it."
Bai raised one finger.
"Correction. Three students that we know about."
Everyone looked at her.
"Why?"
Bai opened her notebook.
"Because the archive was damaged. Several names were removed."
She turned the notebook around.
There were three columns.
The first contained:
SHEN LIN
The second:
PLAYER 18
The third had been crossed out so many times that the paper had almost torn.
Yue frowned.
"What's the third name?"
"I don't know."
"You wrote it."
"I know."
"So how can you not know?"
Bai's expression changed.
"Because every time I remember it, I forget it."
Silence.
Mei leaned forward.
"That's not possible."
"It shouldn't be."
Bai tapped the crossed-out section.
"I wrote the name here three years ago. Then I woke up the next morning and couldn't remember it."
She flipped another page.
The same thing.
A name had been written.
Black ink had been dragged over it.
Then another name.
Crossed out.
Then another.
All of them unreadable.
"Every time I write it," Bai said, "the system removes it."
Mei stared at the pages.
"From the notebook?"
"No."
Bai looked at Lin Xia.
"From me."
Nobody spoke.
Yue slowly wrote:
MEMORY CAN BE ALTERED.
Then underneath:
MEMORY MAY NOT BE EVIDENCE.
Lin Xia stared at those words.
Something about them felt familiar.
Very familiar.
She reached for the pen.
"Add one more."
Yue handed it to her.
Lin Xia wrote:
But written records may be altered too.
Yue looked at her.
"Why?"
"Because the system knows we use records to compensate for memory."
She pointed at Bai's notebook.
"If it can manipulate memory, it will eventually manipulate what we write."
Mei leaned back.
"Then how are we supposed to know what's real?"
Lin Xia looked at the Mahjong tile.
"We don't."
She placed it in the middle of the table.
"We find things that exist independently."
Yue understood.
"Physical evidence."
"Yes."
"Multiple witnesses."
"Yes."
"Something the system can't change without revealing itself."
Lin Xia nodded.
"Exactly."
Bai looked at the tile.
"Then we need to know what this means."
Mei opened her laptop.
"I already started."
She rotated the screen.
There were dozens of images.
The black symbol.
Room 318.
Bai's device.
The Mahjong tile.
The archive screen.
The ranking system.
Mei had placed them side by side.
"They're not identical."
Yue leaned closer.
"What?"
"Look."
Mei zoomed in.
"The symbol on the device has one break."
She pointed.
"The one in Room 318 has two."
Then she enlarged the Mahjong tile.
"This one has three."
Lin Xia's eyes narrowed.
"And the system symbol?"
Mei pulled up a screenshot.
The symbol appeared beside the words PREDICTION MODEL.
It had four breaks.
Nobody spoke.
Mei whispered:
"It's changing."
Bai shook her head.
"No."
She looked at the four symbols.
"It's developing."
At ten fifteen, the school bell rang.
Students flooded the hallway.
For a moment, everything looked normal.
People laughed.
Someone complained about homework.
Two students argued over a card game.
A group of first-years were crowded around a table watching a Go match.
A teacher walked past carrying books.
Nobody looked frightened.
Nobody acted as if the world was broken.
That was what made the school so unsettling.
It could look completely ordinary.
Yue walked beside Lin Xia.
"Do you remember anything else?"
Lin Xia shook her head.
"Pieces."
"Like what?"
"A room."
She paused.
"A table."
"Mahjong?"
"Yes."
"Shen Lin?"
"Yes."
"And the third student?"
Lin Xia stopped walking.
She closed her eyes.
There was something.
A voice.
Female.
Very close.
She could almost hear it.
Don't let it finish learning us.
Lin Xia opened her eyes.
"Girl."
Yue waited.
"She was a girl."
"That's new."
"I think so."
"What did she look like?"
Lin Xia frowned.
"I don't know."
"Name?"
"Nothing."
"Anything?"
Lin Xia's expression tightened.
"A red notebook."
Yue's eyes widened.
"Bai had one."
"No."
Lin Xia shook her head.
"This was different."
"What was written on it?"
Lin Xia swallowed.
"I don't know."
The school bell rang again.
Except this time, it sounded wrong.
One long tone.
Then silence.
Every student in the corridor stopped.
Lin Xia looked around.
Nobody moved.
A boy holding a drink remained frozen halfway through raising it.
A girl with books against her chest stood perfectly still.
Someone's dropped pen hung strangely close to the floor.
Yue whispered:
"What is happening?"
Lin Xia couldn't answer.
The lights flickered.
Once.
Twice.
Then the hallway screen turned on.
Every screen in the school showed the same message.
SPECIAL MATCH
PLAYER 18
PLAYER 4
STATUS: INTERRUPTED
Below it:
RESUMPTION WINDOW: 23:59:41
The timer began counting down.
23:59:40.
23:59:39.
Mei stared.
"That's tomorrow."
Bai's face had gone pale.
"No."
Yue looked at her.
"What?"
Bai stepped backward.
"It isn't tomorrow."
She pointed at the screen.
"The system doesn't count from twenty-four hours."
"Then what does it count?"
Bai looked at Lin Xia.
"Until the match."
Lin Xia's stomach tightened.
"What's wrong with that?"
Bai's voice dropped.
"The last time Player 18 was scheduled to play Player 4..."
She stopped.
Lin Xia waited.
"What happened?"
Bai looked at the frozen students around them.
"They disappeared."
The lights came back.
Everyone moved again.
The boy lifted his drink.
The girl continued walking.
The dropped pen hit the floor.
Nobody noticed anything.
Except the four girls.
Yue looked at Bai.
"Who disappeared?"
Bai shook her head.
"I don't know."
"How many?"
"I don't remember."
"Then how do you know it happened?"
Bai's eyes moved toward Lin Xia.
"Because I wrote it down."
That afternoon, they went to the archive.
Not Room 318.
The main archive.
The place where the school's player records were stored.
They didn't enter through the normal terminal.
Mei used a maintenance computer.
Yue stood behind her.
Bai watched the door.
Lin Xia held the Mahjong tile.
Mei typed:
PLAYER 4
The screen loaded.
SHEN LIN
STATUS: INACTIVE
LAST RECORDED ACTIVITY: 3 YEARS, 2 MONTHS AGO
Mei frowned.
"Same time."
She typed:
PLAYER 18
The screen loaded.
LIN XIA
STATUS: IMPORTED
REGISTRATION: UNAVAILABLE
LAST RECORDED ACTIVITY: 3 YEARS, 2 MONTHS AGO
Yue whispered:
"They started at the same time."
Mei nodded.
"Or were imported at the same time."
Bai suddenly said:
"Search Player 19."
Mei typed.
The screen changed.
PLAYER 19
STATUS: ACTIVE
NAME: UNKNOWN
FIRST RECORDED ACTIVITY: 3 YEARS, 2 MONTHS AGO
Lin Xia stared.
"Player 19?"
Bai stepped closer.
"Search 20."
PLAYER 20 — UNKNOWN
STATUS: DELETED
FIRST RECORDED ACTIVITY: 3 YEARS, 2 MONTHS AGO
"21."
PLAYER 21 — UNKNOWN
STATUS: DELETED
"22."
PLAYER 22 — UNKNOWN
STATUS: DELETED
Mei stopped.
"How many are there?"
She searched the range.
Players 18 through 27 had all been created within the same time period.
Ten accounts.
Only one had a name.
Lin Xia.
Yue stared at the screen.
"Ten."
Bai whispered:
"Ten players."
"No."
Lin Xia shook her head.
"Not players."
She pointed to the timestamps.
"Experiments."
The room went quiet.
Then the terminal displayed a new line.
EXPERIMENT 01 — COMPLETE
EXPERIMENT 02 — COMPLETE
EXPERIMENT 03 — COMPLETE
EXPERIMENT 04 — COMPLETE
EXPERIMENT 05 — COMPLETE
EXPERIMENT 06 — COMPLETE
EXPERIMENT 07 — COMPLETE
EXPERIMENT 08 — COMPLETE
EXPERIMENT 09 — FAILED
EXPERIMENT 10 — ACTIVE
Mei stared.
"Which one is us?"
The screen answered.
EXPERIMENT 10
Then:
PRIMARY SUBJECT: PLAYER 18
Lin Xia's face went cold.
Yue immediately stepped in front of her.
"No."
The screen changed.
SECONDARY SUBJECT: PLAYER 4
Bai whispered:
"Shen Lin."
Then:
OBSERVERS: PLAYER 19–27
Mei's breathing slowed.
"They weren't players."
"They were observers," Yue said.
"Of what?"
The screen flickered.
For the first time, an old video appeared.
The image was grainy.
Three university students sat around a table.
A younger Lin Xia.
Shen Lin.
And the girl with the red notebook.
The three of them were laughing.
The video lasted only five seconds.
Then the audio became clear.
Shen Lin said:
"If the system can predict human decisions..."
The girl with the red notebook interrupted.
"Then eventually it will predict us."
Younger Lin Xia looked directly at the camera.
And said:
"Only if we let it."
The video stopped.
A new line appeared.
EXPERIMENT 10 — PREDICTION FAILURE
Then:
SUBJECT 18 REFUSED TO BE PREDICTED.
Lin Xia stared at her younger self.
For the first time, she understood something.
The system hadn't chosen her because she was unpredictable.
It had chosen her because she had been unpredictable before.
She hadn't become its problem.
She had always been its problem.
Then another message appeared.
PLAYER 18 CHEATED.
Yue frowned.
"What?"
Mei stepped closer.
"That's impossible."
The message remained.
PLAYER 18 CHEATED.
Then:
PLAYER 18 WAS CHEATED.
Lin Xia's eyes narrowed.
Two contradictory statements.
She looked at Bai.
Bai understood immediately.
"The system is saying both."
"Why?"
"Because one of them is true."
Lin Xia stared at the screen.
"No."
She slowly shook her head.
"Maybe both are."
The terminal went black.
Then one final sentence appeared.
YOU WERE NOT THE FIRST PLAYER TO CHEAT.
A pause.
YOU WERE THE FIRST PLAYER TO CATCH THE SYSTEM CHEATING.
The screen went dark.
Nobody moved.
For several seconds, there was only the sound of the archive room's ventilation.
Then Lin Xia looked at the Mahjong tile in her hand.
The black symbol seemed almost invisible now.
She turned it over.
A second line had appeared on the back.
Three tiny characters.
Then a number.
18
And beneath it:
YOUR MOVE.
Lin Xia looked at the others.
"We have until tomorrow."
Yue nodded.
"For the match?"
Lin Xia shook her head.
"For whatever happened three years ago."
Mei closed the archive terminal.
"And if the system doesn't want us to find it?"
Lin Xia placed the tile into her pocket.
"Then we'll make it regret teaching us how to look."
Behind them, somewhere deep inside the school, a Mahjong tile clicked against another.
Then another.
Then another.
Four tiles.
Exactly as Lin Xia had heard that morning.
She turned toward the sound.
Nobody else moved.
And from somewhere beyond the archive door came a quiet voice.
A girl's voice.
Almost a whisper.
"Lin Xia."
Lin Xia froze.
The voice came again.
"Don't let him win."
She opened the door.
The corridor was empty.
But on the floor, directly outside the archive, lay a red notebook.
Open.
Waiting.
And on the first page, written in handwriting Lin Xia somehow recognized, were four words:
WE CHEATED FIRST.