They came for him in the middle of the night. Strange shadows moving on the walls of his room; misshapen forms looming large in his bleary vision; the flawless white surface of a mask as its owner bent over his bed, black smudges for eyes, a cruel sardonic slit of a mouth curving upwards in a vicious smile: these were the fragmentary images he saw in a scant few seconds of wakefulness. He had time to gasp, but not to cry out. A sickly sweet chemical smell invaded his nostrils and something damp and moist and bitter-tasting was clamped over his mouth. His eyelids fluttered frantically like birds' wings beating against the bars of a cage.

And then darkness descended swiftly, its suffocating touch rough and uncaring…

He quickly became aware of the ropes tied tightly around his wrists and ankles, and the wooden bench digging into his back. Sights and sounds, however, filtered through to his mind only gradually, their significance elusive and indistinct. Chanting ebbed and flowed around him, lapping at the shores of his consciousness. He couldn't quite make out any of the words, but there was something in the way that they overlaid one another that made him feel queasy. Or perhaps that was just the after-effects of the foul-smelling rag that had been pressed so tightly against his mouth.

His eyelids seemed heavy and sluggish, but, with an effort, he forced them open. Above him was a high vaulted ceiling, shrouded in shadow. With nothing nearer on which to focus, a wave of nausea rushed through him and he struggled reflexively against his bonds in a pointless attempt to stop himself from falling.

Of course, he remained flat on his back, bound to the wooden bench and, despite the discomfort and growing unease he felt, his cheeks flushed with embarrassment at his foolishness. Footsteps – soft, muffled sounds – drew nearer and the chanting grew muted. He sensed a presence standing over him and tried to turn his head to see.

"He's awake." The murmuring voice was feminine and quivered with barely-restrained excitement.

"Can we start now?" For a brief moment, the voice seemed maddeningly familiar, but he couldn't quite place it. His eyes tried to focus on the speaker, but, from his low vantage point, all he could see was her robes, wrapped tightly around her body, the swell of her bosom looming unnaturally large in his sight. There was something wrong with the girl's face. No one should have a face that colour. Perhaps the girl had been in some kind of accident. Perhaps she suffered from some terrible disease. Perhaps…

"Yes. Why not?" A second voice, strong and confident, tinged with an edge of educated refinement, interrupted his thoughts. "Let's start now!"

Hands were suddenly on him, expertly tearing at his nightclothes, exposing the pale skin beneath.

The chanting, which had appeared to be diminishing into nothing more than background muttering, unexpectedly grew in volume. He thought he could make out individual voices now, straining, imploring. He twisted his head round wildly, trying to make out who was touching him, caught glimpses of blood red robes, of masks grinning obscenely, of pale skin glowing beneath them in the half-light. He saw candles burning fitfully in ornate iron stands, but they were unlike any candles he had ever seen before. They were black, bloated things, exuding greasy flames in a half-hearted attempt at illuminating the darkened vault.

He renewed his struggle against the bonds that held him, but he was simply too weak to loosen them.

The second figure was bending over him, its mask streaked with red and dirty green. A blade glinted dully in its hand.

The first figure – the girl – leaned over. She was close enough for him to see the eyes behind the mask, see them glint with hunger as she gazed at him. No. Not at him. At his chest, pale and small, exposed to the chill night air. The knife hovered for a moment and then its blade pressed gently against his skin.

There was no pain, as such – just a slight stinging sensation and the coolness of the blade as it scored a delicate circular pattern into his skin – just above his heart. He whimpered, tugging once more at his bonds, but he knew he was helpless. And something else held him - a creeping fear, dark and icy, settling over his body, an impenetrable sheath of intangible force, heavy against his flesh. The girl giggled, but the other masked figure, the one with the knife whirled round angrily, shouting at unseen forms in the shadowy recesses beyond the candlelight.

"Keep going, you useless fools! Keep going or it won't work!"

The chanting commenced again, this time stronger, more urgent, bearing before it a hysterical edge that seemed to cut into his mind. The man whose words of command had marked him out as being the leader bent over him once more and his red and green mask suddenly appeared in the very forefront of his sight, blocking out the echoing darkness of the ceiling and the black, engorged candles. Involuntarily, his eyes focused on the red and the green and, with a sudden shock of revulsion, he noticed for the first time small clumps of matter within the paint.

"Won't be long now," the man murmured, his words slightly muffled from behind the mask. "Just have to speak the words…" He paused for a moment, holding his head perfectly still, and then his voice rang out clear and distinct against the background of fervent chanting.

The 'words' were unknown to him. But he could feel their wrongness in his mind. He tried to recall the stories his mother had told him. Stories of the Emperor protecting the weak and the vulnerable. Stories of His agents, the mighty Space Marines, arriving in the nick of time to set free the captive and mete punishment to the oppressor. He tried to remember, but the 'words' – alternately sibilant and seductive, then harsh and glottal – seemed to steal those memories, leeching them of their immediacy and colour, filling his mind with… something else. Something… monstrous.

"No…" he moaned, writhing against the ropes burning his wrists and then he gasped as pain blossomed like a razor-edged flower within his chest. He groaned with pain. There was a fire in his body – a furnace flame that charred his skin. Expecting to see tongues of fire engulfing his torso, he cast a terrified glance down to his chest and gasped again – this time in shock. He was bleeding. Oh, Throne, he was bleeding!

The strange circular mark seemed to throb on the left hand side of his chest. It glowed a dull angry red and, even as he watched, it seemed to darken, turning crimson, then rust red, then black. He was dimly aware of the leader speaking the words, shrieking and moaning and spitting and snarling, of the girl giggling, of the black candles guttering, of the chanting rising to a crescendo. But his eyes were fixed on the mark on his chest. As he watched, the black blood bubbled up through the hairline scoring. And continued to flow upwards – drawn by some unseen force off his chest and hanging glistening in the dimly lit air, each bead seeming to represent a distinct and self-contained world of torment and hatred and pain. He followed their progress, even as, in some distracted part of his mind, he noted that the pain in his chest was subsiding.

The droplets of black glistening blood seemed to be drawn towards a point some twelve inches above his chest. As he watched, these droplets seemed to disappear, to be swallowed into the darkness somehow. The chanting around him had taken on a hushed reverence. To his mild surprise, he found he could not look away from that point above his chest. The empty air seemed to shimmer for a moment. The leader of this strange band of robed people sighed and fell silent. The red-masked girl giggled again, nervously.

The empty air bulged. And then it was empty no longer.

A stain was growing in the air above him, filthy black, smeared at the edges with turquoise and violet, bright shards of colour that somehow made the air around which they flowed and danced darker and more oppressive. He swallowed and tried to cry out, but the fear had taken hold of him now, constricting his throat and drying his mouth. The stain continued to grow and he saw that it was spinning lazily, turning over and over just inches above his chest. With sudden understanding, he saw that, in just a few moments, the moving, swelling knot of darkness would soon touch his naked chest. He noticed that the mark – whatever it had been – was now gone; saw that his skin was untouched and clean, save for the beads of sweat that gathered on its pale expanse. But the stain was growing, the darkness that was its substance now shot through with streaks of angry red, the violets and turquoises fragmenting into brighter colours that he had no name for, but whose intensity threatened to overwhelm his terrified mind. He saw the trailing edge of a tendril of violet light brush against his skin and instantly felt a terrible nausea wrench at his stomach. A thicker finger of red-veined darkness dipped down onto and then through his chest and he screamed – not in pain, but in understanding. For he knew what was coming now.

He knew.

It started with a long, desolate sigh and a sudden rush of displaced air. The stain hung motionless for a brief instant and then its middle distended and stretched. He heard a loud wet tearing sound and a translucent claw-like appendage suddenly appeared at the very apex of the distension. It moved in a swift circular motion as if questing for something. It stretched and strained and, inch by inch, an accompanying arm, glowing dully in the red and violet light, emerged from the bulging blackness. It brushed blindly against his chest and neck, fingers grasping at his soft skin. Its touch was ice and fire. Involuntarily, he closed his eyes and this time found he could scream his terror.