I eased out of the shaft.

Two guards, midnight-clad in their legionary colours. Night Lords both. One had his back to me. Moving silently I slipped my hand around his gorget, smothering his vox-grille with my palm, and twisted.

The other saw me too late, a little farther down the corridor. He saw my eyes first – he saw them when I chose to open them after I killed his comrade. Two fiery orbs, burning vengefully in the darkness. Shadows were the province of the VIII but they were not the only Legion who could dwell in darkness. Balanced on the edge of the shaft, dropping the body of the first guard to land with a dull metal-hitting-metal thunk, I pounced.

The second guard was raising his bolter. It must have felt like gravity had exerted itself fourfold over his muscles; every movement glacially slow in the face of a primarch’s concerted attack. He aimed for my chest, going for the centre mass as instinct would have urged him to. I carried the guard down as I landed upon him, my fingers clamping around his trigger hand and mashing it into the stock of his bolter so he – and it – would never fire again.

He hit the ground, grunting as my sheer weight and power dented his chest plate and cracked the fused ribcage beneath. I masked his scream with my hand, crushing the vox-grille, breaking teeth. Blood geysered up through his ruined war-helm, splashing hot and wet against my face. I kept squeezing, immune to the guard’s panic.

Then it stopped, and silence followed.

Still straddling the dead guard’s body, I looked up and tried to get my bearings.

A long corridor stretched out in front of me: bare metal, faintly lit, nondescript. I could be anywhere on Isstvan. I remembered little of my abduction from the battlefield. What happened between when Curze appeared and my waking in the cell might never return.

A sense of enclosure as I touched the metal wall on my left made me suspect I was underground. Perhaps Horus had ordered the construction of tunnels beneath the surface. I wondered if there were cells for Corax and Ferrus too. I dismissed the idea almost as soon as it was formed. Horus did not take prisoners of war, it wasn’t in his nature – though I had much cause to question exactly what his nature was over these last few months. This was Curze’s doing.

I knew then he hadn’t forgiven me for Kharaatan, for what I did to him.

My brother was a petty-minded, shallow creature; this was his way of evening things up between us.

Taking the bodies of the guards, one by one, I threw them down into the pit. I suspected much of this place was deserted – after all, Curze had left me here to die – and no one would hear the crash of their broken bodies when they hit the ground, but a pair of dead Night Lords out in the open would arouse alarm immediately. A few seconds gained might be the difference between my escape and continued incarceration.

With the guards dispatched, I padded gently to the end of the corridor, slowing as I reached the junction and listening intently for sounds of disturbance.

Nothing.

Peering around the corner, I saw another passageway, empty like the one I was just leaving.

The peace didn’t last. After a few minutes, I was halfway down the next corridor when a door slid open along the right-hand side and a legionary stepped out.

Acting with greater alacrity than his dead brothers festering in the pit, he opened up a comm-channel and sounded an alarm.

‘Vulkan lives!’ He sounded afraid, and the irony of that fact gave me a cruel satisfaction as I ran at him. I took a glancing hit from a hurried snap shot, before I smashed the flat of my palm against his chest. It was a heart strike, which, if delivered with enough force, can kill instantly. His primary organ collapsed – so, too, the secondary back-up. The legionary crumpled and I left him for dead, racing into the chamber from where he’d come as the sirens started screaming.

Again, I was confronted with more bare metal. No weapons, no supplies, nothing. It was spartan to the point of being deserted. Except I heard them coming for me above the wailing alarms. Some were shouting in that ugly, guttural language of their home world; others hurried in silence, the drum of their booted feet betraying their urgency and panic.

I crossed the room, rushing through the only other exit, and found another corridor. It was shorter than the previous one but just as barren, yet I had begun to feel a familiarity for this place. Around the next junction I almost charged into a pair of guards who were coming the other way. I killed them both swiftly, lethal damage inflicted in less than the time it took for me to blink. I stole one of their chainblades – it was the only weapon I could take and use effectively – wondering how I would escape, trying to formulate some kind of plan.

I needed to find somewhere to stop and think, adapt to the changing situation.

I went up.

The ceiling duct was tight against my body, and I had to discard the weapon I had only just procured, but by replacing the overhead grate I could temporarily mask my point of egress.

It stank in the vent, of blood, of sweat, and I wondered where exactly it was ferrying air from and to. Crawling on my belly, using my elbows and toes for propulsion, I reached another grate that looked down onto a room below.

Banks of monitors surrounding a much larger screen showing a schematic of the prison marked it as a security station. Unaugmented human serfs were in attendance, speaking into vox-units, desperately trying to find me. No legionaries were visible. They were hunting, attempting to establish a trap.

These men and women were not warriors, but they were allied with my enemies.

If I were to escape, none could live.

Quietly removing the grate, I slid through the opening head first and dropped down amongst them. A woman, her face daubed in Nostraman tattoos, cried out and I backhanded her across the chamber. Going for his sidearm, one of the male operators tried to draw down on me but I was faster. Much faster. I killed him, too. In fewer than three seconds, all six human operators were dead. I made it quick, as painless as I could, but failing to salve my conscience in the process.

The schematic on the screen showed only a portion of the underground complex. Again, I was struck with a sense of familiarity concerning the layout and wondered how massive this prison actually was. The other monitors showed pict-feed images of the search teams, linked up to retinal lenses. Data inloaded from the legionaries’ battle-helms ran across the screens. Heart monitors on every Night Lord thrummed agitatedly below the feed from each helm-corder, graphic equalisers slaved to their voice patterns rose and fell as they breathed and hissed orders.

I ignored the pict-feeds, focusing on the half-map instead and committing it to memory.

Two doors led out of the security chamber. I took the one that, according to the schemata, led to an upper level. I had no idea how far down beneath the Isstvan surface I was, or what would be greeting me when I got there, but there was no other course for me to take.

Another corridor faced me, at the end of which was a cross-junction. Halfway down, I paused and shook my head to clear it.

‘Where am I?’ I breathed, not recognising this junction from the schematic. I had an eidetic memory – this should not have been happening. I considered going back but the risk was too great. By entering the ducts above I had gained only a few seconds against my pursuers. I had to move on. And fast.

Reaching the junction, I paused again. Two more corridors stretched away from me, the destination of each concealed in darkness. A faint breeze, detected by the tiny hairs on my bare skin, flowed from the right. I was about to take that branch when I saw a shadow seemingly emerge out of the darkness.