At first, the sound wasn't even an alarm.
It began as a low pulse — mechanical, steady — echoing through the steel bones of the vault. Then the tone deepened, split, and multiplied. What started as rhythm became distortion.
The vault lights dimmed. A red strip flickered across the walls, like veins under skin.
"Mira," Stitch said softly.
She didn't answer.
He saw it in her posture before she spoke — her head tilting slightly, her breath catching. "Someone's inside the grid," she whispered. "They're reading us."
"How—?"
"I don't know. Move."
The hum became a shriek. Warning glyphs bloomed across the vault walls, lines of red text in half-broken code:
INTRUSION DETECTED — PROTOCOL 7 LOCKDOWN INITIATED
Mira lunged to the console, fingers flashing over the keys. "I can override the first tier. Not the second."
"Meaning?"
"Meaning we run."
The vault door shuddered. Outside, metallic steps gathered like thunder. Stitch could feel it through his shoes — the tremor of armored weight descending the hall.
He lifted the data core, sealed it into the pack. It hummed faintly against his chest — warm, almost alive.
"Mira—"
"Go!"
She was already moving, her coat slicing through the light. Stitch followed, pulse hammering. The corridor ahead flashed with strobes — red, white, red again — shadows fracturing with every beat.
They reached the first junction just as the vault behind them sealed shut with a hiss of pressurized air.
The intercom clicked to life.
"Unauthorized extraction in Sector K-47. Deploy counter-units."
Mira swore under her breath. "They've got hunters."
The first explosion came from the far end of the hall — a concussive blast that sent a wave of heat and dust through the corridor. Stitch hit the ground, rolled behind a vent column. Shards of glass and light fell around him.
"Mira!"
"I'm here," she called — emerging from the smoke, eyes glowing faintly through her rain-soaked fringe. "Move left!"
They sprinted through the narrow passage, boots echoing on steel. Behind them, mechanical footsteps closed in — the rhythm unnervingly precise.
They hit a dead end — a service hatch locked by magnetic seal.
"Pulse key," she ordered.
Stitch slammed it against the panel. Nothing. The lights sputtered.
"It's fried!"
Mira glanced at the ceiling. "Boost me."
He crouched, she stepped into his hands, and he pushed her up toward the vent grid above. She jammed a blade between the bolts, forcing it open, sparks raining down.
"Go!" she said, pulling him up after her.
They crawled through the narrow duct — the metal vibrating with the sounds of pursuit. The hum of drones. The hiss of pneumatics. The bark of commands distorted through comms.
Then — silence.
The kind that hums louder than sound itself.
They emerged onto a maintenance platform high above the SubGrid's reactor floor. Below, coolant mist rolled over endless machinery — pistons, pipes, turbines the size of buildings. The scale of it all dwarfed them, two shadows lost in a living engine.
"Route?" he asked, panting.
Mira checked her wristlink. "There's an exit shaft on the west end. But it's exposed."
"Define exposed."
She gave him a look that said enough. "Thirty meters of open air. And nothing to land on if we miss."
He grinned despite the situation. "So… parkour?"
Her lips twitched. "Something like that."
They ran.
Across the catwalks, through the hiss of steam vents, across rusted beams that bowed under their weight. The city's hum bled through the walls — distant sirens, advertising jingles, the thrum of endless life beyond the storm.
Behind them, the first of the hunters appeared — black armor, faceless, rifles humming with charge. Energy bolts hissed past, scorching the metal rails.
"Go!" Mira shouted.
Stitch vaulted a gap, landed hard, rolled, came up running. He turned in time to see her leap — body silhouetted against the blue haze, hair streaked with rainlight — and he reached back instinctively, catching her wrist as she landed.
The contact was quick, electric. For a moment, the chase paused — the world reduced to breath, rain, and the thrum of her pulse under his hand.
Then she pulled free. "We're not done yet."
They reached the shaft — a vertical tunnel of light plunging into the city's underbelly. Wind screamed through it.
"There," Mira said, pointing to a faint ledge halfway down. "Landing bay conduit. Aim for it."
He looked down. "That's suicide."
"Only if you stop halfway."
And then she jumped.
No hesitation. Just air and motion and rain.
Stitch cursed, took three steps back, and dove after her.
The fall was a blur — gravity and adrenaline colliding, the light of Echelon-5 spinning around him. The city stretched infinite, the noise folding into silence. He saw her below — twisting mid-air, catching a beam, rolling into the conduit with perfect precision.
He hit a second later, the shock rattling through his bones.
For a moment, neither of them spoke. The sound of their breathing filled the narrow shaft.
Then Mira laughed — low, breathless. "Welcome to Ghostline."