The testing bay held hundreds of geological samples in various stages of examination under powerful brass-cased microscopes, or lying in chemical baths now dried out. There was nothing there that suggested anything valuable enough for the outpost to be attacked. The control room that overlooked the bay was empty too, its cogi-tators ritually sealed with runes of inaction to appease the machine-spirits as they were shut down.

'We should take what information they still hold.’ said Shen. 'At least we'll have some idea of what work they did here and who was involved. They might even have pict-recordings from the sentry guns, so we could see who attacked them.'

'I am no tech-priest.’ said Aescarion. 'Do you know how to operate all this?' She indicated the banks of cogitators that covered the walls of the control room, with blank readout screens.

'We'll just take the memory units.’ said Shen. Thaddeus has men who can open them up.’

'Movement.’ said Mixu, glancing at the auspex screen. 'Somewhere above us.’

'Probably more underhivers.’ said Shen, drawing his pistol.

A hand plunged down through the ceiling of the control room, grabbing Shen by the collar of his armour and dragging him up sharply, slamming him into the metal ceiling. The hand was encased in a gauntlet of purple ceramite.

'Fire!' yelled Aescarion and bolter fire ripped up into the ceiling beside Shen, who was trying to bring his inferno pistol to bear. Before he could get a shot up he was dragged through the ceiling completely the metal tearing as his armoured body disappeared from view.

Sister Aescarion was the first after him. The hole in the ceiling led to what must have been the outpost's main shrine, where ranges of pews carved out of solid carbon faced an altar formed from the casings of a giant cogitator. Pipes and valves knotted the walls so the chapel was contained entirely within the body of the cogitator, and when operational its readouts would have bathed the shrine in a glow of information. Now it was dark, so the scene in front of her was lit only in the flashes from the light mounted on Shen's armour.

It was a Space Marine. Its armour bore the chalice symbol of the Soul Drinkers on one shoulder pad. It carried no weapons.

Aescarion caught a glimpse of its face. In life the skin had been dark but now it was pasty and mottled grey with disease. The eyes were gone and dark ragged holes stared blindly. The lower part of the face had been gnawed away and the bleached white of jawbone and teeth grinned out. Nothing living could look like that, and nothing dead could stare with such blind madness and hate. Sister Aescarion only had the briefest glimpse by the swinging light on Shen's armour, but in an instant there was no doubt.

A Soul Drinker, claimed by the plague. The bullet scars on its armour suggested that it had been mortally wounded in the battle for the outpost, that it had been left behind by its colleagues, and succumbed to the terrible plague that had savaged Hive Quintus. It was the first time Sister Aescarion had actually set eyes on a member of the Chapter.

As she watched, trying to get a clear shot, the dead Soul Drinker tore Interrogator Shen's arm off at the shoulder in a crimson crescent of blood. The arm holding the pistol was flung to one side of the chapel and the rest of him to the other, his armoured body crashing limply into the wall.

Sister Mixu was beside Aescarion, firing her twin pistols. She snapped off two rapid head shots, blowing a hole in the Marine's forehead, but the Soul Drinker seemed not to even notice the massive wound. Aescarion couldn't claim to know a great deal about fighting the living dead but she hazarded a guess that it would take more than just a killing wound to fell the Soul Drinker - nothing but dismemberment would stop it. And dismemberment was something at which Aescarion excelled.

She drew the power axe and charged the Marine. It was a full head taller than her but she was much quicker. Her blade flashed down and she hacked deep through the Marine's collar and into his torso, the axe's power field splitting his fused ribcage and carving through dead organs.

The Marine gripped the haft of the axe, pivoted, and flung Aescarion into the brass-cased altarpiece-machine. The casing buckled beneath the impact and components rained down as Aescarion slid to the floor. Telltales flashed on her armour's retinal display and a brief flash of pain dulled to an ache as painkillers flooded her system.

The Soul Drinker stood above her, staring blindly down with its dried-out eye sockets. Bolt pistol fire ripped into its back from the Seraphim emerging into the chapel behind it, punching through the tarnished armour and kicking chunks from its skull. Its broken face grinned down as it reached for Aescarion.

Aescarion tried to roll out of its way but her body wouldn't respond - she must have shattered a shoulder and maybe a hip. The Soul Drinker picked her up by the shoulder joins of her breastplate and began to pull, trying to crack her open like a predator opening up armoured prey to get at the flesh inside.

Aescarion could feel her armour coming apart. Her good arm still held her axe and she felt its power field humming. As the telltales flashed red on her retina she dragged the blade into the waist of the Soul Drinker. She used every ounce of her strength to cut through the ceramite power armour, but she had no leverage and her system was struggling to cope with the pain.

One of the Seraphim wrapped an arm around the Marine's neck from behind, trying to saw its head off with her combat knife. The Marine turned and drove an elbow into the Sister's midriff, knocking her backwards. It let go of Aescarion with one hand as it did so. She planted one foot onto the floor of the chapel and swivelled on it, ripping the axe blade through the waist of the Space Marine, cutting clean through the ceramite and the Marine's spine., Aescarion slumped to the floor. The upper part of the Soul Drinker's body fell beside her. Its legs stood for a moment, then fell to one side, clattering against the metal of the chapel.

The Seraphim picked herself off the floor and stood over the upper half of the Soul Drinker. It looked up at her, head jerking as the end of its severed spine flopped like a beached fish. Aescarion handed her the axe, and without switching on the power field, the Seraphim cut off the Soul Drinker's head.

Mixu was on the other side of the room, tending to Shen.

'He's dying, sister.’ said Mixu. Two of the Seraphim helped Aescarion over to where the interrogator lay. Gore pumped from the torn shoulder socket, forming a thick pool beneath him. His eyes were open but they couldn't focus on anything and though his jaw worked no sound came out. Mixu opened up the breastplate of the carapace armour and Aescarion saw right away that the interrogator was beyond hope. The ribs had been broken and separated by the force of his arm being torn off, and then crushed when he hit the wall. The organs inside must have been torn to shreds.

As Aescarion watched, Shen died.

'He was a soldier of the Emperor.’ said Aescarion, grimly aware of her own injuries. 'We cannot let him rise again.’

The Seraphim carried Shen's body down to the turbine floor, where they placed a long-fused krak grenade in his mouth and reduced the corpse to a rain of ash.

Aescarion was no tech-priest and only knew enough of the Machine-God's dogma to maintain her own battle-gear. She had the Seraphim lever off the casings of cogitators in the control room and remove what she took to be the datacores inside. Aescarion herself removed a plaque on the wall of the control room that recorded all the adepts who had ever worked in the outpost - hundreds of names inscribed in tiny letters on a sheet of brass. As an afterthought she took the head of the dead Marine, and sealed it in a specimen box from the lab, along with the Marine's bolt pistol that was still in its holster with its golden chalice symbol.