In the dead of night, Yin Yu stepped into the library, searching for the materials she needed.

Chapter 2: Rules descend upon...

Yin Yu’s nails dug deep into the hardcover of the dictionary. The check-out record bearing Gu Shaoqing’s handwriting began to bleed. The bold strokes of ink spread like spiderwebs, crawling across the window and shattering the moonlight.

*"Avoid perilous states..."* He had barely uttered the second character when the fluorescent lights on the entire floor exploded. Li Xiaochen’s scream was drowned in the cacophony of shattering glass, leaving only the cold blue glow of electronic screens in the darkness.

**[00:00:00]**

**[Newbie Protection Lifted]**

The slithering, scratching noises surged tenfold. Yin Yu dragged Li Xiaochen beneath the lectern. As his phone flashlight swept across the room, they saw the creature pressed against the door’s glass pane—it had once been a medical student in a white lab coat, now with half a surgical mask dangling from its left cheek and a gray rat gnashing its teeth from its hollowed right eye socket.

*"Close your eyes!"* Yin Yu barked.

Li Xiaochen instinctively curled into a ball, hearing the crisp rustle of pages flipping wildly overhead. When the *Modern Idiom Dictionary* slammed into the mutated creature’s face, he opened his eyes to the most surreal sight of his life:

Seven gray rats hung mid-air, legs flailing as if gripped by invisible hands. Eight steel rods writhed like centipedes, pinning the monster to the doorframe. The glowing characters *"Seven Up, Eight Down"* shimmered in the air before disintegrating into stardust that vanished into the dictionary.

*"This thing’s cooler than my protractor!"* Li Xiaochen peeked out, only to be shoved back under the lectern by Yin Yu.

The pinned creature convulsed violently as the rats screeched like wailing infants. Watching the golden light fade, Yin Yu yanked his junior toward the corridor: *"The skill only lasts five minutes!"*

The green exit signs behind them burst one after another, like ghostly lanterns lighting their path. Yin Yu’s canvas shoes crunched over shattered plaster models as Li Xiaochen panted between strides: *"C-can you teach me that move later?"*

*"Maybe after you piece together the notes you shredded last week."*

*"That was innovative destruction—*look out!"*

Li Xiaochen suddenly grabbed Yin Yu’s collar, sending them both tumbling into a storage room. Outside, bone-chilling cracks echoed—a janitor-uniformed mutant stabbed a broom down its throat, its rotting fingers emitting a mechanical drone: *"...detected...violators..."*

Yin Yu’s pupils constricted. The creature’s chest bore a library staff badge, its embedded screen flashing: **[Punishment Enforcer No. 01]**.

*"It’s hunting us,"* Li Xiaochen whispered, his cold sweat dripping onto Yin Yu’s hand.

A sudden *ding* from a charging power bank pierced the silence.

They turned stiffly to see Li Xiaochen’s waterlogged phone booting up in the corner. The mutant’s neck creaked like rusty gears as its decaying face swiveled toward the storage room.

*"Run!"*

Yin Yu burst through a side door just as the shelves collapsed behind them. Li Xiaochen’s scream caught in his throat—the mutant’s broom now sprouted a chainsaw, its blade dripping with gore.

*"This way!"*

The sign for the reading room ahead made Yin Yu freeze. Three days ago, a calligraphy piece reading *"Silence"* had hung there; now, it oozed blood-red: **[Forbidden]**. Foul green sludge seeped from the doorframe, reeking of formaldehyde.

Li Xiaochen skidded to a halt: *"Don’t go in! I smell burning adhes—"*

He was cut off as the mutant slammed into him. The chainsaw grazed Yin Yu’s ear, embedding into the wall. Sparks flew as the creature’s badge flickered: **[Insufficient credits warrant elimination]**.

*"Credits?"* Yin Yu rolled away from another strike, the dictionary flipping pages on its own. *"Xiaochen, take cover!"*

*"This room’s all bookshelves!"* Li Xiaochen ducked behind the service counter with *Structural Mechanics* in hand. The textbook suddenly burned hot, pages flipping to a chapter on bending moments. A blue glow rendered his palms translucent.

As the chainsaw descended toward Yin Yu’s skull, a shrill bell echoed through the library.

**[Morning Broadcast Test]**

**[Now Announcing Freshman Guidelines]**

Every mutant froze. Yin Yu kicked the chainsaw aside and hauled Li Xiaochen toward the elevator. As the doors closed, a mechanized voice boomed:

*"Rule 1: The library operates on a credit system..."*

The mirror inside revealed their ragged silhouettes—Li Xiaochen’s down jacket spewing feathers, Yin Yu’s scarf hanging in tatters. When all floor buttons lit red, Li Xiaochen pointed at the mirror: *"Words! There’s writing!"*

Fluorescent text materialized, mirroring Gu Shaoqing’s penmanship:

Escape Rules

1. Each floor corresponds to a department’s curriculum. Check credits at B1.

2. Failing students become cleaners (e.g., our recent friend).

3. Team status cannot be revoked unless...

The final line was smeared by a bloody handprint. Li Xiaochen scrubbed with his sleeve, revealing half a formula: **∫Probability of Death = 1**

*"Do math majors always have to be this cryptic?"* He grimaced, clutching his broken protractor. *"Where now?"*

Yin Yu pressed the B1 button, watching golden light ripple across the dictionary. *"To find out how Gu Shaoqing predicted this."*

The elevator’s descent churned their stomachs. Li Xiaochen stared at a fire hydrant: *"Senior...did that mutant look like the librarian who went missing last week?"*

Yin Yu’s fingers twitched. Three days ago, that librarian had cheerfully wished him *"Good luck on finals"* while checking out *The Literary Mind*. Now, her badge swung from the mutant’s chest.

The doors opened to a stench of decay. Li Xiaochen stepped forward but was yanked back by Yin Yu—

The B1 archive floor was paved with faces.

Or rather, tiles plastered with student ID photos. Each bore bloody credit scores, some numbers dwindling before their eyes. Yin Yu spotted Xiao Ming’s photo—his credits plummeted from **[12]** to **[0]**, flipping the tile to reveal **[Eliminated]** in crimson.

*"Get back!"*

A dragging noise echoed from the shelves. Yin Yu raised the dictionary as a girl in a lab coat emerged, polishing a display case. When she turned, Li Xiaochen gasped: *"Tan Meng? The med school intern? Wasn’t she at the hospital?"*

Tan Meng’s silver badge gleamed: **[Librarian - Trainee]**. Her blood-soaked rag wiped a specimen jar—inside floated Xiao Ming’s student ID.

*"We meet again."* She smiled, lifting a spray bottle reeking of disinfectant. *"Here to check your credits?"*

Yin Yu’s gaze dropped to the golden badge on her coat: **[Current Credits: 58]**.

Tan Meng’s disinfectant spray hung mid-air, the "84" label on the bottle blurred by bloodstains. Yin Yu stared at the "58 credits" on her chest badge, suddenly recalling the *click* of Xiao Ming’s tiles resetting to zero—a sound eerily similar to the*** printer spitting out failure lists.

“Move.” Tan Meng’s rubber soles crushed a student ID photo beneath her feet, eliciting a faint whimper from the boy trapped beneath the tiles. As she bent to wipe the display case, a scalpel slipped from her lab coat pocket, fresh blood droplets sliding down its blade.

Li Xiaochen suddenly gripped Yin Yu’s arm: “Senior! That’s Senior Gu’s…”

Atop the glass case, a student ID floating in formaldehyde read: **School of Mathematics and Computing, Gu Shaoqing**. The photo showed a cold-eyed young man, but the credit column glared **[-20]**.

“Negative credits? How?” Yin Yu’s dictionary burned faintly in his hand.

Tan Meng’s spray bottle screeched across the glass: “He tried hacking the system core and triggered a penalty.” Her smile bloomed sweetly, like during anatomy demos. “Now he’s a walking virus reservoir. Every floor he steps on doubles the course difficulty.”

Li Xiaochen’s glasses fogged: “Should we…?”

“Stay away?” Tan Meng flicked Gu Shaoqing’s ID with her scalpel tip. “Too bad you’re teammates.” She swung the blade at Yin Yu’s throat—

“**Hua Di Wei Lao!**”

Yin Yu’s roar shook the archive. Tan Meng’s blade froze half an inch from his throat, a crimson ancient “*” (prison) character materializing beneath her feet. Li Xiaochen gaped as the math department senior froze mid-swing, a puppet paused mid-performance.

“Idiom skills work on admins too?” Yin Yu wiped his nosebleed. Golden text glowed on his dictionary’s newest page: **[Hua Di Wei Lao: Immobilize a single target. Cooldown: 15 minutes]**.

Li Xiaochen breathed on the glass case: “Senior Gu’s credits are rising!”

The formaldehyde solution bubbled as the number jumped from -20 to -19, blood threads clinging to the ID. Yin Yu whirled toward the tiles—every minute they survived added 1 credit to Gu’s score.

“He’s paving our path with his life.” Yin Yu gripped his dictionary, recalling the death probability formula from the elevator. As Tan Meng’s eyes twitched, he yanked Li Xiaochen deeper into the archives: “Find the student registry!”

Moldy paper crumbled under their fingers. Li Xiaochen sneezed while flipping through 1983 graduate records until Yin Yu seized his shoulder: “Do these shelves look like bridge trusses to you?”

The underclassman’s glasses flashed: “A three-hinged arch! The keystone’s at—” He pointed to the chandelier dangling from the ceiling.

The shelves collapsed with a roar. Tan Meng’s stilettos screeched across metal as she closed in: “Clever underclassman. No wonder you’ve lasted this long.”

Li Xiaochen wedged a popsicle stick into the shelves—last week’s model workshop scrap—halting their collapse. Yin Yu finally understood why Gu lured them here: this was an architecture student’s domain.

“Third row, southeast corner!” Li Xiaochen cried. “My *Architectural Mechanics* textbook is vibrating!”