The steel door leading into Floor 5 slammed shut behind them with a deep, heavy boom.

  The sound didn’t stop at the door.

  It ran down the metallic corridors like a living thing—echoing, colliding, folding back on itself—until it became a low rumble that felt less like noise and more like something breathing in the dark.

  Ten flinched and turned instinctively, pressing his palm to the wall as if the cold metal could anchor him.

  Ahead wasn’t a simple hallway.

  It was a space so vast their eyes needed a few heartbeats to adjust—an entire city of steel, carved into corridors and dead ends, stacked with suspended walkways and stairways that led nowhere, with conduits snaking along the ceiling like the intestines of an enormous machine.

  Above them, massive gears rotated slowly, shedding fine metallic dust that drifted down like ash.

  The air was cold and dry.

  It smelled like old machine oil, stale iron… and a faint trace of ozone, as if electricity had discharged somewhere far away only moments ago.

  Z-69 raised a hand and brushed the armor plate John had modified for him.

  His fingers caught a fresh scratch—thin, sharp.

  Dark blood still clung to the seam.

  The night they had survived on Floor 4 wasn’t over.

  It had simply been replaced by a different kind of hell.

  Jin spat to the side, grimacing at the metallic taste that never left his mouth these days.

  “So this is floor 5.” he muttered.

  Ten’s voice came out small.

  “Why… is it so quiet?”

  As if the labyrinth had been waiting for that question, invisible speakers embedded in the ceiling crackled to life.

  A mechanical voice—flat, emotionless—spread throughout the maze like a verdict.

  “Floor 5 – Judgment.”

  “Assessment: Intelligence – Judgment – Decision-Making Capability.”

  “Environment: Mechanical Labyrinth.”

  The words lingered, then continued without mercy.

  “Objective: Each contestant must obtain one key and find an exit from the labyrinth—or die.” “notice: Keys cannot be shared. Lacking a key will result in disqualification from progression.”

  Ten stared upward, lips parting slightly.

  “Keys can’t be shared…?” he repeated, like he’d misheard.

  Jin let out a humorless laugh.

  “Translation: we’re allowed to walk together right up until the moment we find something worth killing each other for.”

  Z-69 didn’t speak.

  He simply looked down the corridor ahead, eyes narrowing in a way that made Ten’s skin prickle.

  A moment later, the ceiling lights snapped on.

  Pale yellow illumination poured down in uneven patches, like broken street lamps in a slum district.

  Some corridors were bright.

  Others were dim.

  Some flickered, as if undecided.

  The labyrinth had no obvious central axis.

  Everything looked disturbingly similar.

  A deliberate design choice.

  Ten crouched and examined the floor.

  Along the edges of the corridor ran shallow grooves like drainage channels—dry, for now.

  In places, those grooves were interrupted by long scrape marks, as if entire walls had once moved and ground against the floor.

  “This maze…” Ten murmured. “It’s not fixed.”

  Jin glanced at him. “Meaning?”

  Ten swallowed. “Meaning… it can change. It can rearrange itself. If we memorize routes, it might punish us for it.”

  Z-69 moved forward slowly, head tilted slightly up—watching the lights.

  He wasn’t just looking for a path—he was searching for a pattern.

  They passed the first three intersections without encountering anything except faded wall markings: half-scraped arrows, jumbled numbers, and deep claw gouges that looked like someone—or something—had tried to carve its way out.

  Jin stepped closer to one set of gouges and dragged his fingertips along the groove.

  His nails scraped metal.

  The sound lingered longer than it should have—echoing in a way that felt wrong, as if the labyrinth had caught the sound, held it, and then released it reluctantly.

  Ten’s shoulders rose.

  “That… sounded like footsteps.”

  Jin snorted. “In a place like this, I doubt we’re alone.”

  Z-69 stopped in front of a wall marked by three parallel grooves.

  Three deep, straight claw marks.

  Not random.

  Almost… deliberate.

  Like a sign left for whoever came next.

  He brushed away a thin layer of metallic dust from one groove.

  The dust clung to his fingers like cold ash.

  This text was taken from Royal Road. Help the author by reading the original version there.

  And then—

  The light overhead flickered.

  Once.

  Ten jerked his head up.

  Flicker.

  Twice.

  Jin’s expression tightened immediately, instincts flaring.

  Flicker.

  Three times.

  The lights went out.

  Darkness slammed down so fast their eyes couldn’t adapt.

  Everything vanished.

  The world became cold air, slow grinding gears, and the sudden awareness of their own breathing.

  Then—

  Click.

  A sound, faint but precise.

  Not the soft slap of a shoe on the ground.

  A metallic tap—like claws touching the floor at perfectly even intervals.

  Click… click… click…

  Ten’s breath caught.

  The clicking changed direction immediately, as if whatever made it had reacted to the sound of Ten’s inhale.

  From somewhere further away came a slow scrape against the wall.

  Krrrk… krrrk…

  Deliberate.

  Patient.

  As if inviting their imagination to assemble a shape from sound alone.

  Then whispers rose around them.

  Not words.

  Not a language.

  Just a rustling noise, like wind passing through pipes—too close, too intimate, as if the maze itself were whispering directly into their ears.

  Ten’s heartbeat started to race.

  He could hear it.

  He was sure the darkness could hear it too.

  Then suddenly, a pillar of red light erupted at the far end of the corridor, like a blood-colored torch driven into the floor.

  Jin didn’t wait for orders.

  “Run!”

  They sprinted.

  The red pillar was their only reference point, but the labyrinth was not straight.

  The floor rose unexpectedly.

  Ten nearly tripped.

  Z-69 grabbed the back of his collar and yanked him upright.

  At that exact moment something swept past where Ten’s head had been—no visible body, no clear outline—only a patch of darkness denser than the rest, trailing a coldness like ice brushing exposed skin.

  Ten’s throat locked.

  A shiver shot down his spine so sharp it felt like pain.

  Jin dragged Ten into the red-lit zone first.

  Z-69 entered last.

  As Z-69 crossed into the light, the red pillar trembled faintly, like an overloaded conduit.

  The whispers stopped at the edge of the light.

  They didn’t cross.

  But they didn’t leave either.

  They waited—like hunting dogs held back by an invisible leash, listening to the prey breathe and deciding which one tasted easiest.

  Then the overhead lights came back on.

  Pale yellow illumination returned.

  The corridor looked… normal.

  No footsteps.

  No scraping claws.

  No whispers.

  Ten collapsed onto the floor, clutching his head.

  Jin leaned against the wall, chest heaving.

  Z-69 stared back into the corridor they’d fled.

  There was nothing.

  No marks.

  No trace—

  Except a thin layer of frost clinging to the wall, as if something cold had passed through moments ago.

  Ten swallowed hard.

  “I think… it was chasing me.” he whispered. “I could feel it.”

  Jin nodded, voice quieter now. “Same. It’s like… it could hear my heartbeat.”

  Z-69 stayed silent.

  He replayed the sequence.

  When Ten’s breathing spiked, the clicking shifted toward them faster.

  When they forced themselves to calm down—when Jin held his breath—those sounds slowed, searching.

  But one detail bothered him.

  The darkness had tracked Ten.

  It had tracked Jin.

  Yet Z-69 himself…

  Had felt like a blind spot.

  His hand rose unconsciously to his chest.

  His heart was dead.

  His pulse was a lie manufactured by a crystal.

  Could it be—

  Ten looked up, still shaking. “What is that thing?”

  Z-69 answered with the cold honesty of someone who didn’t waste words.

  “A predator that hunts fear.”

  Jin snorted weakly. “That’s poetic.”

  They moved again while the lights stayed on.

  This time, nobody spoke much.

  Ten tried to regulate his breathing—slow in, slow out—like he’d been taught to swim in panic water.

  Jin walked ahead, eyes scanning every corner.

  Z-69 stayed in the middle, one hand always brushing the wall as if reading braille.

  He was collecting information: the timing of the flickers, the distribution of light, the direction of airflow, the density of dust on the floor.

  Two more intersections.

  Then a four-way junction opened up.

  Each corridor bore a different mark on its wall.

  One had three parallel claw marks.

  One had a scraped-out arrow.

  One bore an upside-down 7.

  And one…

  One was unnervingly smooth.

  Clean.

  Too clean.

  The metal wall there was almost polished, like it had never been touched.

  Jin pointed to the clean corridor immediately.

  “That one. Fewer marks usually means fewer dead people.”

  Ten’s stomach tightened.

  “I… don’t like it.”

  Z-69 stared at the clean corridor.

  He didn’t like it either.

  Not because it felt dangerous in a straightforward way.

  Because it felt like a trap designed for people who choose safety.

  “It’s too clean.” Z-69 said.

  Jin frowned. “So what? Maybe nobody went that way.”

  Ten shook his head, voice thin. “Or maybe nobody came back to leave marks.”

  Jin opened his mouth to argue—

  The light overhead flickered.

  Once.

  All three looked up at the same time.

  Flicker.

  Twice.

  Z-69’s hand shot out.

  He grabbed Jin by the shoulder and yanked him backward away from the clean corridor.

  Flicker.

  Three times.

  Lights out.

  Darkness poured in—and immediately, from the clean corridor came the clicking.

  Closer.

  Clearer.

  As if whatever lived in the dark had been standing there the entire time… waiting for them to choose wrong so it could open its eyes.

  Ten let out a small involuntary gasp.

  The darkness shifted direction instantly—like sharks smelling blood.

  A pillar of red light flared up in the corridor marked with the three claw scratches.

  Z-69 didn’t speak.

  He shoved Jin forward, grabbed Ten by the arm, and ran toward that corridor like running toward a decision he’d already made.

  This chase was worse.

  The labyrinth began to move.

  A wall slid sideways in the darkness with a sound like a coffin lid being dragged.

  A narrow gap opened—then snapped shut like a crocodile’s jaw.

  Jin skidded to a stop just in time and grabbed Ten by the collar, yanking him through.

  Ten stumbled, losing breath in a sharp hiccup.

  The whispers swelled.

  For a terrifying second, it sounded like laughter.

  Z-69 realized it wasn’t laughter.

  It only sounded like laughter—the maze’s feedback loop, the sound the darkness produced when fear rose high enough to become a signal.

  Behind them, the clicking grew closer.

  Then—silence.

  That was worse.

  Because predators didn’t go silent when they lost prey.

  They went silent when they got close enough to strike.

  Ten’s breathing started to accelerate again.

  Z-69 squeezed Ten’s wrist hard.

  Ten flinched.

  “Breathe.” Z-69 said, low. “Slow.”

  Ten tried.

  In—slow.

  Out—slow.

  The red-lit zone appeared ahead like a wound in the corridor.

  They crossed into it.

  The pillar trembled.

  The whispers stopped at the border.

  The clicking halted like it hit glass.

  Then lights returned.

  Jin leaned against the wall and laughed once—sharp and shaky.

  “What kind of sick game is this floor playing?”

  Z-69 answered without looking at him. “A judgment test.”

  Ten wiped sweat from his forehead, hands still trembling. “It… it follows our fear.”

  Jin looked at Ten. “And it follows our breathing too.”

  A cold silence settled.

  The maze’s predator wasn’t supernatural.

  It was engineered.

  A hunting algorithm wrapped in darkness.

  They moved again while the lights stayed on.

  Deeper in, the markings on the walls began to form a pattern.

  Not guiding symbols placed by the Tower—

  But signs left by contestants who had lived long enough to leave traces.

  At many intersections, along the edges of the walls, there were claw marks—always exactly three—positioned at the same height, like a standardized warning.

  Jin crouched near one and frowned.

  “Three marks… means what?”

  Ten thought quickly. “Maybe it safe pause points. Places where people stopped and lived long enough to scratch the wall.”

  Z-69 nodded slightly. “Or places where the red light activates.”

  “Which means the maze has… anchors.” Jin said slowly. “Fixed safety nodes.”

  Ten’s voice was tight. “And probably fixed kill zones too.”

  They turned another corner and saw something else.

  A dark red smear stretched across the wall, long and uneven.

  It looked like someone had dragged a bleeding hand while stumbling forward.

  Human blood.

  Ten touched it lightly, then jerked his hand back.

  “It’s… still fresh.”

  Jin’s expression darkened. “Must be from one of the groups ahead of us.”

  They followed the direction of the smear.

  It led toward a narrow passage where the light barely reached.

  At the entrance of that passage, on the wall, someone had carved a symbol.

  A small circle with a vertical line inside.

  A crude drawing.

  But unmistakable.

  A key.

  Ten’s breath caught. “That’s…”

  “A key sign.” Jin finished, voice low. “Someone marked it.”

  Z-69 stared at the symbol.

  He didn’t rush.

  This floor punished rushing.

  He looked at the floor grooves—how dust gathered, how airflow moved.

  He looked at the overhead lights and the spacing between flicker points.

  Then he spoke, calm as a blade.

  “We go in.”

  Ten swallowed. “What if it’s a trap?”

  Z-69’s eyes didn’t leave the corridor.

  “It’s Floor 5.” he said. “Everything here is a trap. The only difference is whether we can see through it or not.”

  Jin exhaled slowly. “Well. Judgment, huh?”

  Ten forced his hands to stop shaking.

  “I’ll… I’ll watch the ground.”

  Z-69 nodded once.

  “Do that. And when the lights flicker…”

  Jin’s mouth tightened. “We don’t panic.”

  Ten whispered, as if repeating it made it true. “We don’t panic.”

  They stepped into the narrow passage, following the blood smear and the carved key symbol, moving deeper into the mechanical labyrinth.