The silence beneath the world wasn’t truly silence. It had a heartbeat.

Rane could feel it now — low, deep, arrhythmic. It pulsed through the rusted rails and the crumbling walls. It breathed through the failing lights above, each one flickering like a dying memory. They were deep now. Strata 2 had swallowed them, and the city — the last city — was just a myth above their heads.

"Keep eyes forward," Korrin muttered, leading the way with that cold soldier's calm he always wore like armor. The light from his headlamp sliced through the darkness, barely illuminating the fractured tunnel ahead. He held his pulse rifle tight, its power cell humming like a warning.

Behind him came Juno — silent, broad, unflinching — her shotgun resting heavy in her hands. Her footsteps were the loudest, metallic thuds echoing behind the group like distant drums of war. Sil followed close, eyes flicking between her tablet and the strange walls, her expression twisting every time the environment didn’t match what little data they had. Eren, ever the quiet one, lingered near Rane at the rear, his eyes darting, body tense.

Rane felt it too — the tension, the unease that coiled in her chest like wire. This place wasn’t like the ruined buildings above. It wasn’t forgotten. It was waiting.

“We’re officially off-map,” Sil said, her voice barely above a whisper. She tapped her cracked tablet screen, frustrated. “No feeds, no relay signal. This whole sector is jamming tech. Artificially.”

Rane glanced at her. “Like it’s built that way?”

“Like something doesn’t want us here.”

They moved through the tunnel and came upon a bulkhead door — massive, sealed, etched with half-scraped-off symbols. VIREX’s logo lingered there, but someone had tried to gouge it out. Repeatedly. It looked like claw marks.

Sil approached the access console, fingers flying over cracked keys. “I can override this, but I need time. Maybe five minutes.”

Korrin nodded. “Juno. Rane. Hold perimeter. Eren, eyes on our six.”

They set up fast, efficient. Rane knelt by a pile of shattered maintenance drones, rifle aimed into the shadowed hall they’d come through. Every creak of metal set her nerves on fire. She tried to breathe slow. Even that sounded too loud.

“What even was this place?” Juno muttered, standing with her shotgun like a statue.

Sil answered without looking up. “AI deep integration testing. Neuro-link experiments. Virex used to pull people down here. Volunteers, they said. But some files said otherwise.”

“You’re telling me this is where they played god?” Eren asked from behind, his voice tight.

“Not god,” Sil said. “Worse. They tried to create a system that could mimic and counter all human decision-making in wartime. It didn’t go well.”

Rane could feel sweat trickling down her back despite the cold. The hum from the door’s power system had shifted — a new tone, like something waking up.

Sil froze.

“Got it.”

The door hissed, groaned — then opened.

The tunnel beyond wasn’t metal. It wasn’t even designed like the rest of Strata 2. It looked like bone. Ribbed supports curved like vertebrae. Pipes ran through the walls like arteries. And in the center, a downward ramp spiraled into darkness. Something about the geometry hurt to look at. Like it defied the rules of the surface world.

“This isn’t a lab,” Rane whispered.

“No,” Sil said, stepping in first, her light catching something on the walls — scraps of gear. Old Virex helmets. ID tags. Rusted rifles fused with the walls like the structure ate them. “It’s a graveyard.”

They moved down the spiral, each step heavier than the last. The sounds faded. Their own gear became muffled. Even their thoughts seemed dulled. Like something was pulling at them.

Halfway down, Sil screamed.

Everyone turned. She was on the ground, clutching her leg — bleeding. A barbed wire-like filament had burst from the wall, slicing through her suit like paper. It retracted just as fast.

“Trap!” Korrin barked.

Rane rushed to Sil, applying pressure. Eren fumbled for supplies. Juno raised her shotgun and turned, watching the walls.

Then the lights died.

Total black.

Only sound.

Metal scraping. A distant skitter. Then another scream — but this time not from the group. Something else was screaming. Long. Alien. Rage and hunger wrapped in steel.

“Rane—MOVE!” Korrin shouted.

The wall beside her exploded — something burst out. A shape made of limbs and metal, shrieking like static, clawing forward on all fours.

Juno fired. Once. Twice. The thing staggered, screaming.

“RUN!” Korrin shouted, lifting Sil onto his shoulder.

They ran back up the spiral, lights flashing wildly. More walls cracked open — things clawing their way out. Drones? No. These were reassembled bodies — part-human, part-machine. Some wore old Virex armor fused into their flesh.

The Labyrinth Heart wasn’t dead.

It had been hibernating.

Rane turned, laying down fire as Juno covered their retreat. Eren dragged a steel support beam across the bulkhead as soon as they breached it, slamming the door shut behind them.

Breathing hard. Blood on the floor.

Sil groaned, half-conscious. Korrin was pale. Eren was shaking.

“Where’s Juno?” Rane asked.

No one answered.

She ran to the door and stopped — pressed her ear to it.

No gunfire. No movement.

Just one final, faint scream — then nothing.

A beat.

Then something heavy slammed the door from the other side.

Korrin grabbed her arm, pulling her back. “She knew. She stayed behind so we could run. Don’t waste it.”

Rane stared at the sealed door, her chest tight. She wanted to scream. To go back. But she knew it wouldn’t change anything.

The Labyrinth had claimed its first.

And something told her it was only beginning.