I’m still unpacking the access codes, we reply. The files are huge.

Quick as you can. Hollows closing.

We glance back at them. It’s going as fast as I can make it.

But Salt is holding up a finger. Hear that?

We stand in the quiet, listening to the creep of distant footsteps.

There, says Bor. Yes?

Salt’s machine counts a beat on his fingertips. There. And there.

What’s happening? asks Hail.

The contacts aren’t getting any closer.

But they’re still walking, says Bor, matching the count.

Hail watches their fingers, ticking in time. The hollows don’t know what we’re here for, and there’s nowhere to manoeuvre in here. Maybe they’re taking their time, making sure they don’t trip an ambush.

When have they ever done that? we ask. When have they ever held back?

Cover me, says Bor, without warning.

Hail’s machine puts out a hand, flashing Wait—!

But Bor is already turning the corner, her footsteps almost as light as our own, in a machine that’s nearly twice our size.

We’ve barely lost her heat-ghost when she tears back into view, ducking the zip-and-crash of something hard and fast and sparking.

“Door! Door!” she shouts on open channels.

The deck shakes under a rush of heavy feet, rings out as another hardshot skips off the plating. Salt doesn’t wait. His Decatur takes the rusted bulkhead door by its lip, presses its knee against the nearby wall and heaves. Steel screams and the huge hatch shivers in place, but it doesn’t move. Hail rolls up behind him, and the two machines pull together, buckling deckplates under the pressure, moulding deep fingerprints into the metal. The hatch is made to survive containment loss or a sudden burst of cooking ammunition, to lock down against a furnace failure or a haywire shell coming out of the repair-works, but against Hail and Salt it’s helpless. They haul it off its hinges, and slam the door into its frame so hard it fuses.

“What happened?” shouts Hail.

“They’re right on top of us,” says Bor. “The hollows overhead were making noise so we wouldn’t hear the creepers.”

Another round skips off the bulkhead, beats a bulge into the metal right above Hail’s head. “Rook?” she calls.

The last of the cipher rolls out ahead of us: a plain of fractal calculations, twisting forever. “We’ve got the key,” we reply. “Unlocking.”

We edge closer to the silver vault and offer a connection to the systems that keep it locked. Something takes on the other side, but there’s no handshake, no broadcast ID. We send our own again, say our names and sketch ourselves out for it to see, but all we get is silence.

“Rook!” Hail shouts over the net, between ringing hardshots.

“Working on it!”