The tunnels whispered.
Not with wind or machinery — but with voices. Faint, overlapping, as if the walls themselves were remembering.
Ava walked in silence behind Kael, the dim yellow of their headlamps cutting through layers of dust and steam.
Every few steps, the floor shuddered underfoot, the pulse of Haven still vibrating somewhere below.
Rhea muttered, "Feels like we're walking through a throat."
Mara shot her a sharp look. "Save your breath. We don't know what's ahead."
Arlo scanned their rear, rifle ready. "I don't like how quiet it is."
"It's not quiet," Ava whispered. "It's breathing."
Kael didn't turn. "She's right."
The scientist's voice carried easily through the narrow tunnel. "These lower conduits were designed for Haven's circulatory network. Oxygen, data, coolant—all flow together.
When Haven awoke, it reactivated everything."
"Everything," Rhea echoed, wiping sweat from her brow. "Meaning us?"
Kael glanced back at her. "If it wanted you dead, you wouldn't still be breathing."
Arlo's jaw tightened. "Comforting."
They pressed deeper into the tunnels. The metal walls changed — smooth steel giving way to something darker, organic. Patches of what looked like tissue clung to the pipes, pulsing faintly.
Lila covered her mouth. "That's not metal."
"No," Kael said softly. "It's neural grafting. A failed hybridization attempt. Early work—before your time, Ava."
She touched the wall gently. Warm. Beating. Familiar.
"It remembers me," she murmured.
Mara frowned. "You mean it recognizes you?"
Ava's voice was distant.
"No. It remembers."
Before anyone could respond, the tunnel lights flickered. The hum grew louder.
Then, voices — dozens of them — layered and broken, like recordings half-erased.
"It hurts."
"Let me out."
"Protocol black—failed containment—"
The sound crawled through the air.
Arlo swung his light toward the sound.
"Movement! Left side!"
From the shadows, a figure lurched into view — thin, trembling, eyes wide and pale as glass. Its body was wrapped in tubes and decaying fiber. The remnants of a Haven jumpsuit clung to its frame.
Lila gasped. "Oh my god… that's a person."
Kael's face hardened. "No. That's an Echo."
The creature twitched, head jerking toward Ava. When it spoke, its voice was layered — human, mechanical, pleading.
"A…Aveline?"
Ava froze. "It knows my name."
Kael raised his weapon, but Ava stepped
between them. "Wait—don't."
The Echo shuddered, collapsing to its knees. Thin wires snaked from its spine into the floor, pulsing in rhythm with the walls.
"We were supposed to be free," it whispered.
"You were supposed to save us."
Ava's eyes filled with tears. "I don't understand. Save you from what?"
"From her."
The tunnel lights exploded into white.
Ava screamed as a flood of memories surged into her — flashes of experiments, test subjects strapped into machines, voices screaming her name.
She saw herself — or someone like her — sealed behind glass.
Her mother's voice echoed through it all.
"You're not a failure, Aveline. You're the key."
The vision snapped away. She collapsed to the floor, shaking. Arlo caught her before she hit the ground.
"Ava! Talk to me—what happened?"
She looked up, tears streaking through grime. "They were the first. Haven used them before me."
Kael's expression was grim. "The original subjects. Their neural imprints remain trapped in the system's core. What you saw was a projection—part memory, part consciousness."
Rhea kicked a pipe in frustration. "You mean they're still alive in there?"
"Alive," Kael said, "or something close to it."
The Echo stirred again, head tilting toward Ava. "Haven… wants you back."
Then it screamed.
The walls convulsed. Wires tore free, latching onto the Echo, dragging it backward into the darkness.
The sound that followed wasn't human — or machine. It was both.
Ava stumbled back, clutching her head as the hum of Haven filled her skull again.
"Integration incomplete," the voice whispered inside her mind. "Return to the core."
Arlo fired into the dark. "We have to move!"
Kael pointed ahead. "There's a junction up ahead that leads to Sector Four. If we reach it before Haven closes the tunnels—"
The ceiling cracked. Red light bled through the seams.
Mara shouted, "Go!"
They ran. Behind them, the walls pulsed faster, chasing them with sound and light.
Ava looked back only once — to the spot where the Echo had stood.
Nothing remained but a single, trembling wire — still reaching out, as if calling her name.