2:41 a.m.

  The air inside the D City Metro Operations Center hung heavy, as if frozen in place. Greenish light from the control screens flickered against the metal walls—cold, like the last trace of warmth on a corpse.

  Lin Duo sat motionless, his back fused with the master console, like a fractured shard jammed into the system’s anatomy. His eyes locked onto the live feed from Line 7. Bloodshot, unfocused.A can of coffee sat on the edge of the desk, tilted, its surface smudged with fingerprints and a faint lipstick stain. It wasn’t his. It didn’t belong to tonight.

  He was on his third night shift in a row. His mind wheezed like an aging engine choking in fog, but he refused to shut his eyes. He knew: the moment the operator sleeps, the system might decide to wake up on its own.

  Crack—The screen stuttered. The green display jolted, like something unseen had pierced through it.Lin snapped upright, his fingers tightening on the control stick.On the map, Train 034 vanished for a beat—then reappeared.At a station that wasn’t supposed to exist.

  P0.

  He squinted. The code beneath read: “NULL.”

  No such station existed. Not on any routing chart, emergency protocol, or training manual.As if someone had drawn a dot of ink on the map in the middle of the night and whispered to reality: “Now follow this.”

  Lin held his breath and opened the system log—only two seconds of footage.He rerouted to the audio channel. Static crackled from the speakers, laced with the sound of train doors opening and closing. Then a woman’s voice drifted through, faint as if from the bottom of a well:

  “…someone didn’t get off.”

  Lin’s heartbeat skipped.

  His hands flew over the keyboard, punching in the backup server’s access code. Commands cascaded down the screen like an avalanche of ice.He dove into the redundancy layer—finally, a complete image surfaced.

  The train stood still in a tunnel void of light. Its doors slid open slowly.A single leg stepped out first—wearing a dirty, worn-out school shoe.No figure followed.Just the leg, like a signal. A harbinger.Something had crossed the boundary into reality.

  Lin cursed under his breath.He reached for the screenshot key—The screen blinked out like an eye shutting.

  “Unauthorized access. Record deleted.”

  The console beeped—shrill and insistent, like a guard dog barking into the dark.

  Lin shut the terminal down, forcing himself to breathe. The whir of the ceiling fan circled above like the echo of something deep and old—like a voice from the bottom of a well.

  Then came a sound at the door.

  A dry, creaking groan—screee—like bones slipping from their joints.

  Cao Feng stood in the doorway, collar loose, fatigue etched into the folds of his face. He looked as though just glancing into this room aged him three years. Leaning against the doorframe, he resembled a tired old god watching from the edge of the world.

  “Engineer Lin,” he said, “handover log’s still empty.”

  Lin Duo rose to his feet. His voice was stripped of all emotion. “Feng-ge. Train 034… just made an unscheduled stop. It wasn’t on the route chart. Three minutes long.”

  Cao Feng’s brow twitched. His silence stretched, thick as shadow. Then, quietly:“…You saw it?”

  Lin didn’t nod. He simply looked at him.

  “You’re not new to this job.” Cao’s voice dropped lower, like smoke curling under a door. “You really plan on putting that in the handover log?”

  Lin stepped closer. “What was that station? P0? System flags it NULL, and the footage’s already wiped.”

  Cao bit down on some old memory. Something flickered behind his eyes—tangled, half-drowned.“If you want a promotion,” he said, “stay clear of this kind of thing. My advice? Write: ‘All systems normal.’”

  “Who was on shift before me?” Lin’s voice hardened. “Last week—same time, same line.”

  “…Transferred.” Cao glanced sideways, his eyes dull but still sharp enough to bite.

  “You don’t find that strange?”

  “Transfer. Resigned. Dead.” His laugh was rusted iron. “Take a guess.”

  He paused, then sighed and patted Lin on the shoulder.

  “You’re sharp. Don’t play dumb.”

  With that, he turned and walked away, his silhouette swallowed by the dim corridor beyond.

  Lin stayed frozen, like a sentinel forgotten in the heart of a labyrinth.

  The night hadn’t loosened its grip yet.

  He changed into civilian clothes and took a detour from the operations center toward Line 7’s maintenance entrance.His access card slid through the reader.The gate to the tracks unlocked with a dull click.

  The midnight tracks stretched out like the spine of a dead serpent, each segment lying still in the dark.The air reeked of rust—blended with the scent of old grease and dust.

  Lin crouched low, scanning the rails where Train 034 had stopped. He swept his flashlight along the grooves—until something caught his eye.Wedged between the rails was an object, small and still. Forgotten.Like evidence left behind at a crime scene.

  A student ID.

  Its corners were frayed, and the once-blue cover had faded to a lifeless gray.The photo showed a girl with a ponytail.Eyes clear.Innocent.At the top, three printed characters spelled her name:

  Jiang Yao.

  Lin’s breath hitched.He took a photo of the ID, carefully wrapped it up, and tucked it into the deepest pocket of his jacket.The wind moved through the tunnel again—carrying a sound he couldn’t quite catch. As if something whispered… and then left.

  —

  Back at his apartment. 4:00 a.m.The sky outside was still dark.

  He booted up the internal database and typed: “Jiang Yao.”

  The system replied almost instantly.

  Jiang Yao. Female. Senior year. City Public Transit High School.Status: Deceased.Account closed: Three years ago.Cause of death: Suicide. Fall from height.

  Lin’s fingers froze over the keyboard. His fingertips whitened.The cold began in his gut and crawled slowly upward, wrapping around his throat.

  He reached into his coat for the ID again, needing to see it—

  But something had changed.

  A new line of text had appeared near the top—he hadn’t noticed it before.

  “If found, please return.Thank you for riding.”

  The font was delicate, faint—like it had been pricked into the paper, stroke by stroke, with a needle.Irreversible.

  He locked the ID in a drawer, both hands numb with cold.But by morning, when he woke—the key was still in his pocket.The drawer was still locked.

  And the ID was gone.

  —

  5:30 a.m.

  The sky hadn’t fully brightened, but a faint gray had begun to creep up from the east—Like a dream that refused to end properly.

  Lin sat hunched at the kitchen table, spine curved as though carrying an entire city on his back.His eyes were fixed on the drawer—Still empty.And yet, it felt like it had swallowed something.

  The student ID was gone.

  The lock was untouched. The key had never left his pocket.He forced himself to wonder: Maybe I misplaced it.But that single line of text, etched into the night, felt like a needle lodged in his mind.

  Unauthorized reproduction: this story has been taken without approval. Report sightings.

  And he couldn’t pull it out.

  “If found, please return. Thank you for riding.”

  That line didn’t exist in any of the metro system’s standard phrasing.Lin tore through the internal database, crew protocol documents, even legacy code archives.Nothing.

  The font was slightly crooked, the strokes uneven—like someone had etched the words into the paper with an impossibly fine needle.The paper had yellowed with age, yet the lettering felt… recent.As if it had just been written.And somehow, still warm.

  He unlocked his phone and pulled up the internal directory, scrolling past official channels to a private number.He called.

  Three rings.Then a voice—faint, hoarse, like it had been dragged out of water.

  “…Hello?”

  “Lin Duo. Engineering Team Six,” he said, keeping his voice low. “Last time the P0 anomaly appeared—was it your shift?”

  Silence.

  It spread slowly over the line, thick and moss-covered, like a stone sinking into a midnight lake.

  Then she whispered:“Don’t ask again.”

  Her voice was barely audible, as if something stood right behind her, listening in.

  “You’re not authorized to access that segment.”

  “So you saw it too,” Lin muttered, eyes drifting to the window.Outside, a freight truck rumbled across the overpass, its headlights smearing a dull arc of light across the glass.

  “I didn’t say anything.”

  The call cut.

  The screen went black.

  And stranger still—there was no trace of the call.No record in the phone log.No digital fingerprint.Like the conversation had never happened.

  Lin set the phone down, heart pounding.Someone was scrubbing the tracks.Not just erasing footage—They were wiping calls, locations, system responses.

  And this wasn’t the first time.

  Three months ago, during a Line 7 maintenance sweep, a “blank segment” had also shown up in the logs.They’d blamed it on “equipment vibration” corrupting the data.

  But now he remembered—That incident had also happened early Monday morning.

  He powered up the old terminal, fingers moving with practiced urgency.

  Search terms: “Station–P0,”“NULL Tag,”“Code Conflict–Station ID.”

  The machine groaned to life like something ancient.Its interface loaded line by line,Slow, glitching—as if dragging a memory from deep, reluctant sleep.

  While the system churned in the background, Lin made himself a cup of instant coffee.The kettle hissed softly.He stood in the corner of the kitchen, watching the steam curl upward toward the ceiling lamp—like a spider’s web creeping through the dark.

  Suddenly, the television shrieked.

  A sharp, needle-thin burst of static split the air.The screen flipped—colors inverted, flashing like a metro surveillance feed playing in reverse.Then, in the center of the display, a string of characters flickered:

  [ZERO_ID: LOCATION_NOT_EXIST]

  Lin froze.The remote control lay untouched on the table.

  A second later, the screen snapped back to the news channel.The anchor spoke calmly, without missing a beat:

  “...At 2:44 this morning, Line 7 of the metro experienced a temporary disruption. No official statement has been released at this time.”

  2:44 a.m.Exactly when the P0 event had occurred.

  Lin searched through the transit authority’s site.No alerts.No maintenance announcements.No system disruption notices.

  It was as if the news segment had played for him—and only him.

  He stood abruptly, grabbed his work badge, and swiped into the system’s higher-access layer.This was beyond his clearance level—he knew that.But he also knew waiting for “someone else” would be a mistake.

  Deep in the archives, buried in a cluster of old data snapshots, he found a discarded project file from five years ago.

  Title: Contingency Line – Z

  An abandoned project.Emergency evacuation drill line.The official termination note was bureaucratic nonsense:“Signal redundancy test failed due to interference conflict.”

  The schematics listed four stations:Z0, Z1, Z2, Z3.

  No P0.

  That station had never been part of the plan.Not erased.Not forgotten.

  Never permitted to exist.

  He stared at the monitor, eyes narrowing on the twisted waveform diagrams.One of the interference signals stood out—a recurring spike.

  Every first Monday after the lunar month began,a sharp anomaly appeared in the data.It lasted between 2 minutes and 3 minutes 30 seconds.

  He pulled up a calendar.

  Five days from now.

  That was the next cycle.

  Lin Duo closed his eyes and drew a long breath.

  His scalp tingled.

  His body felt pinned to the chair, as if something unseen held him down.

  This wasn’t a hardware fault.This wasn’t a prank.

  —It was something else.Something that periodically tore open the edges of reality—forging a brief overlap between the city’s transit system and a space with no name.

  He exhaled slowly, gaze dropping to the ID badge in his hand.

  He knew that door would open again.

  He just didn’t know if it would ever close.

  2:32 a.m.Line 7 Control Room.

  The air was thick with the acrid scent of overworked electronics, layered with the sticky staleness of aging plastic—like fatigue so deep it fused skin into vinyl.

  Lin crouched beneath the monitoring console, seated low like a beast in wait, ears covered, breath held.

  He’d dimmed the brightness of the holographic interface until icons faded from his vision one by one, disappearing into the dark.

  He wore no uniform—just a dark gray coat.His face hidden beneath the collar’s shadow.His work badge? Locked in his office drawer. The key twisted three times.

  This wasn’t a shift.

  It was infiltration.

  He brought only one item: a rapid-repair chip.A coin-sized disk sewn into the hem of his inner shirt—his only “legitimate” excuse.The only token that let him slip past the firewall unnoticed.

  The train had entered dispatch range.

  Line 7.Train 034.Sliding deeper into the city’s heart.

  Lin tapped his knee with his fingers—slow, steady. Like a clock ticking.Waiting for the signal.Waiting for a beat not written into this world’s rhythm.

  2:37.

  The train entered Yingshui Station—the last official stop on its schedule.From here, the route was supposed to head straight to the final terminal. No stops.

  But Lin knew better.

  There was another bend in the tracks—a hidden route, buried in a forgotten digital archive that no one ever accessed.

  He was already aboard, disguised as a late-night passenger.

  At this hour, the train was nearly empty—a metal coffin without a name.

  In the fifth car, a drunk man lay sprawled across the seats, his head resting on cracked plastic.He muttered softly, like whispering to someone long dead.

  Lin sat in the third car, leaned against the window.His eyes drifted occasionally toward the chip sewn into his shirt—a faint, pulsing light flickered on its surface.The spectrum it displayed wasn’t meant for passengers.Only internal tech staff would recognize it:a warning.Precursor to an environmental anomaly.

  2:41 a.m.

  The exact moment he’d first discovered P0.

  The train jolted—hard.The lights flickered twice, like someone had slapped the car from outside the tunnel.

  A voice came over the PA—female, robotic:

  “The train is in motion. Please do not lean on the doors.”

  But the cadence was… wrong.

  It lacked the smooth precision of a proper system prompt—more like a voice model cut short halfway through training and shoved onto the stage.

  A second later,it felt as if something huge had shoved the entire train forward.

  Jolt.Drag.Tilt.

  Lin braced himself.Outside the window, the tunnel lights peeled away like broken ribs, yanked one by one from the track of reality.

  And then—darkness.

  Not the kind where light simply fades.

  This was structural.A hollowing of space itself.So black it rang in the ears.

  The chip’s signal began to spike.The train’s coordinates dropped off the grid—off the route map—off the system.

  Into a blank page.

  Lin shot to his feet, heart pounding like a war drum.His eyes locked on the door—and the gap that was just now beginning to open.

  Ding.

  The doors slid apart.

  This wasn’t any platform he recognized.

  What lay beyond was a stretch of damp concrete tunnel—wide.Silent.Lifeless.

  No station number.No screens.No posters.

  Just a single tungsten lamp hanging low from a wire, swaying slightly—a relic from another time.Its glow wavered like a candle on the edge of extinction.

  Lin hesitated at the threshold.One second.Two.

  Then pressed the record node under his shirt.

  His voice, low and steady:

  “2:42. Train has deviated. Current environment unknown.Airborne particulate count… anomalously low.”

  His voice was steady—but carried a tremor barely audible, like a thread stretched too tight.

  He took his first step.

  The moment his foot touched the ground, something clicked—a faint metallic rattle.A loose plate on the rail, shifting ever so slightly.The sound was small, but sharp.Like an invisible mechanism had just been triggered.

  He expected to hear his footsteps echo through the tunnel.

  He didn’t.

  All he heard was water—drip.Drip.Falling from some unseen height.

  Like time itself had taken to dripping.

  He moved along the wall, slow and cautious.Roughly ten meters in, a junction appeared—abrupt, tumor-like, protruding from the concrete.

  A worn cloth sign hung on the wall, yellowed and faded.

  [Station Code: P0]Status: Closed to Public | Trial Operation Phase

  Not a screen.Not a projection.A physical sign—stitched fabric, cracked edges, threads fraying like time itself had forgotten to pull it down.

  Like someone had nailed it there years ago,and no one had dared remove it since.

  Lin reached out.He wanted to touch it.To capture an image.To prove this place existed.

  Then the station trembled.

  Just slightly—like a beast shifting in its sleep.

  Behind him, the train let out a long, low sound:

  “Woooo—”Not quite an alarm.Not quite a scream.

  He spun around.

  The doors were closing.

  He sprinted back, full tilt, pressing himself against cold steel, lunging forward on hands and knees.

  One foot landed inside—and the doors slammed shut an inch from his face.

  He hit the panel.Pounded the door.Pressed the release switch—

  Nothing.

  The train moved.Smooth.Silent.

  As if it had never left the rails.As if none of it had happened.

  Lin collapsed onto the floor of the carriage, gasping for breath.

  He didn’t cry.He didn’t scream.

  He just watched.

  Watched the dark recede as the train pulled away—carried the light with it,leaving only black.

  But in that moment—he saw it.

  Reflected in the train’s window.Two figures.Standing right where he had been moments ago.

  Two versions of him.

  Their faces were blurred—features smudged like water-damaged paintings.Eyes, nose, mouth—melting together under invisible pressure.

  But the frame.The shoulders.The posture.

  Undeniable.

  They were him.

  And he,now,was alone.Left behind.Outside the train.