The first sign was the light.

 

It came on above the bunker doors without warning, washing the concrete walls in a dull red pulse that seemed too slow for alarm and too deliberate for fault. Men looked up at it from tool benches and ammunition crates and half-finished conversations. Nobody spoke. The pulse came again. Red, then shadow. Red, then shadow.

 

Piotr had been carrying a crate of feed belts across the floor. He set it down without meaning to, as if his hands had made the decision for him. The bunker had gone still in the way places only did when everyone in them had heard the same wrong thing and was waiting for the next.

 

Then the engine turned over.

 

The sound hit the room before most of them understood what they were hearing. It was not the bark of a starter or the cough of an idling carrier. It was deeper than that, heavier, as though something buried had just forced air back into itself after a very long time. The floor trembled. Dust leapt from the rafters. A spanner skittered off a bench and rang once on the concrete.

 

At the far end of the bunker, 329 sat in its berth beneath the work lamps, black and immense and still half-hidden in shadow. For one heartbeat it looked unchanged.

Then one of the Vulcans twitched on its mounting.

 

No one moved.

 

The red light pulsed again.

 

The second engine note came harder. The V10s caught properly this time and the whole bunker filled with their roar. It rolled off the walls and came back thicker, a wall of sound that swallowed speech before it was made. Men nearest the berth stepped back on instinct. One crossed himself. Another simply stood with his mouth slightly open, rifle hanging from his hand as if he had forgotten what it was for.

 

The first chain drew taut.

 

Piotr had never thought about how thick those restraint links were until he saw them under load. They had always just been there, black with old oil and bunker dust, hooked into floor anchors sunk so deep into the ferrocrete no one questioned them. Now they stood out in a single brutal line from hull to floor, each link trembling under the strain. The tracks bit. Only an inch at first. Steel on concrete. A low grinding lurch more felt than seen.

 

Then the Vulcans began to spin.

 

That was when the dread truly arrived.

 

The howl rose slowly at first, almost buried beneath the engine mass, then climbed through it, sharper and higher and impossible to mistake for anything except what it was: a weapon system coming awake. It cut through the bunker and into men’s bones. Piotr felt it in his teeth. He saw two troopers near the wall flatten themselves against it as if distance measured in inches might still count for something.

 

Krystan ran for the blast doors.

 

He came out of the side access at a stumbling crouch, boots slamming the floor, one hand catching briefly on the edge of a workbench before he drove on. He did not look at the men nearest him. He did not look at the chains. His attention was all for the door controls. He hit the release housing with his palm, hauled the emergency lever down with the other hand, and threw his weight into it.

 

The shutters above the main doors juddered.

 

Too slow.

 

The first restraint failed with a crack of tearing metal and a spray of rust and stone. Not a neat snap. It ripped free of the floor anchor and whipped back along the concrete hard enough to leave a bright scar where it struck. Somebody ducked. Somebody else shouted something Piotr never heard over the engine.

 

329 leaned into the slack.

 

Smoke poured from the exhausts in black, heavy folds. The hull shifted another fraction forward, then another, slow and terrible and entirely certain. The bunker had not become dangerous because the machine was firing. The bunker had become dangerous because the machine was moving and there was suddenly no doubt that it would keep moving.

Piotr backed away without taking his eyes off it. Around him, the others did the same. No orders were needed. The lane in front of the berth emptied in seconds. Men knew better than to stand there and pretend courage had anything to do with what came next.

 

The doors were half open when the remaining chains gave way.

 

One anchor tore clean out of the floor and bounced once across the concrete. Another parted with a hard metallic report that vanished into the roar. For an instant 329 seemed to gather itself, not like a beast, not like anything alive, but like a mass of machinery resolving an obstacle and finding it insufficient.

Then it came forward.

 

The Vulcans’ scream climbed again. Dust boiled around the track guards. The turret traversed a few degrees as it rolled, not searching for a man or a face, but moving with the cold, unsettling confidence of something already deep inside its own logic. Piotr saw the red target laser flick once across the far wall, then disappear into the smoke.

Krystan was still at the doors, hauling them wider because there was no other sensible thing left to do. Not because he had yielded. Because if he did not, that door was going to stop being a door.

 

Daylight cut in across the threshold in a harsh white seam.

 

329 went through it.

 

For one moment all Piotr saw was the top of the hull passing under the hanging lamps, armour plates shuddering under the loaded torque of the engines, smoke dragging behind it, one spinning barrel group blurring so fast it no longer looked made of parts. Then it was in the open and the bunker seemed to exhale around the space it had left behind.

No one moved for a second.

 

The red light kept pulsing.

 

The roar receded by degrees as 329 rolled out into the yard beyond, but the howl of the Vulcans remained, high and terrible and impossible to hear as anything except promise. Somewhere outside, men began shouting. Not the steady cries of work or drill. The ragged, uncertain shouting of people who had just seen something emerge that should, by any sane measure, have remained buried.

 

Piotr swallowed and found his throat dry as dust. He looked at the broken chains lying across the floor, at the gouges in the concrete, at the empty berth under the lamps.

Then he looked towards the open doors and understood, with the sick clarity of a man who has just realised the rules are different now, that whatever was happening outside, the worst part of it had not been the noise.

 

It was the certainty.

 

For a few seconds before 329 had moved, it might still have been possible to believe it could be stopped.

 

Now no one in that bunker believed that any longer.