An airlock hissed open. Inside it, something moved. Forty-seven minutes later, the crew of the Imperial Merchant Freighter Trident were, effectively, dead.

Sister Superior Anastasia looked again at the darkened shape floating aimlessly through space. Her corvette had found the freighter by chance, but it had now become the focus of her crew's attention. She looked back down at one of the several reports displayed on screens around her.

The Alliance's contacts within the Administratum had been thorough in providing details of merchant shipping. Imperial Merchant Freighter Valla was listed, carrying various raw and processed materials, all too incidental to warrant a larger freighter of their own. The ship was small, outdated and slow. Nothing that would attract any pirate, and intercepted security reports showed that the Imperium considered the whole Core-11 sector to be low-risk.

Anastasia looked to a different report. No signs of hostile boarding, no external evidence of recent combat. The ship's engines were functioning well, intership communications were working. The airlock had been used after the ship's last trip through warpspace. Interesting. There was nothing in this sub-sector, so the ship must have warp jumped to it, intending to make another jump. For some reason they stayed here long enough to dock with something, and the crew disappeared. Had the crew been the target?

Internal scans showed no evidence of combat - Anastasia corrected herself: no evidence of armed combat. The ship's crew was missing, no indication of where they had gone, or been taken. Last entry in the ship's IC recorder was routine, the automatic log entry made before the ship's last warp jump. The airlock control system had recorded a single use, connecting to the freighter Trident. Back to the shipping logs: Trident was carrying a cargo of organic materials to a nearby hiveworld. Nothing out of the ordinary. Anastasia leaned towards the intraship comm unit that connected her to the corvette's control deck.

"Sister Sonia, locate and intercept the freighter Trident. Silent running." The reply confirmed the order, and the ship's engines changed pitch as the corvette pulled away from the Valla.

By the time the corvette Centaur entered visual range of the Trident, Anastasia had a better idea of what had happened. Decryption of the Valla's Inorganic Cogitator main memory had yielded the maintenance logs of the ship's key systems. The Valla had dropped out of warp space in order to cross from one warp drift to another. Forty minutes into their one-hour stay in realspace, the Trident entered sensor range. Valla intercepted, communicated, and docked. The airlock had remained open for just under fifty minutes, after which the Trident had departed on a different course to its previous one, and the Valla had remained drifting in realspace, its crew gone.

Anastasia had vacated the corvette's data suite in favour of the control deck. Although the ship was nowhere near the size of a cruiser, it had most of the functions common to larger ships, albeit on a smaller scale. In this case, Centaur was approaching the Trident on silent running, effectively invisible unless someone on the freighter actually looked out of a porthole and saw them.

"Lifesigns positive," said Sonia, who was now operating the sensor controls, "but indistinct. Possibly as many as a hundred lifesigns, but readings are unclear."

"The Trident's crew was supposed to be one hundred twenty, Valla another twenty," said Anastasia to herself. "What happened to the others? Bring us into docking position. Monitor for communications, but send nothing." Sister Portia, who was steering the corvette, brushed a hand over the thruster controls, turning them to be parallel with the freighter. The small warship attached itself neatly to the side of the towering cargo hauler, with barely a hiss from the braking jets.

Inside, the Trident was darkened. The long corridors were cloaked in shadow, only the pulsing of low-power emergency lights highlighting the walls. The airlock rumbled open, and two armoured figures entered quickly, covering the corridors with boltguns. Another pair followed, one of them holding a flamer, the other with an auspex array, which beeped quietly after a moment.

Anastasia touched a control on her suit's neck, allowing the helmet to retract into its collar. "Atmosphere normal," she said automatically as her small crew did the same. At the touch of a button on her auspex, the airlock sealed itself again. She looked around, and drew her bolt pistol.

"Bridge first," she said quietly. The group moved through the corridors towards the centre of the ship. Anastasia continued to direct her auspex around, but could see nothing threatening. Nothing obvious, she thought to herself.

The bridge was quite small, compared to the expanses of corridors and cargo bays that comprised most of the freighter. The Sisters entered from a hatch in the floor, checking for threats. Satisfied that the chamber was empty, Anastasia crouched down to attach her auspex to the bridge's IC data outlet.

"Sister Zoey," she said after a moment, "how long will decryption take on the main memory?" Zoey dropped the point of her flamer and glanced at several of the bridge displays.

"Two hours, Sister Superior," she answered after a moment's thought, "the IC has double-secure memory modules. I could download the core memory to the Centaur, and let the computer begin basic decryption."

"Do it," said Anastasia. Zoey detached a small transmitter from her armour's backpack, and attached it to a data socket. After a moment a green light blinked on. The Sister Superior retrieved her auspex and looked around.

"Where is the crew," she wondered aloud. She glanced at the auspex again, then turned back to Zoey. "Can we leave the memory to transmit itself?" Zoey nodded. "Cargo decks, then," added Anastasia.

The cargo decks ran for half a mile forward of the bridge. Anastasia and her crew arrived in the monitor chamber, high above the 'ground level' of the freighter. Sonia glanced at the readout on a wall, beside an elevator leading down to the cargo decks themselves.

"All bays are showing full mass," she said. Anastasia nodded, and motioned them onto the elevator. It dropped slowly down, making some random metallic noises as it descended between the giant silo-like cargo bays. Through the occasional porthole they could see the bays themselves, locked in position by massive clamps, the spidery connection corridors running between them like strands of thread. Between the bays they caught a glimpse of space now and then, but after a moment they were too far down to see anything but walls of metal.

The elevator shuddered to a halt at the bottom of its shaft. Zoey led the way, her flamer's pilot light hissing softly. Anastasia followed, flanked by the other two Sisters. After several turns, and a handful of intersections, they came to one of the cargo bay entry ports. A dirt-encrusted digital readout showed the serial number of the bay connected on the other side of the door. After two attempts at activating the worn-out control, the door creaked open. The Sisters stepped through, into the darkness beyond.

"Lights," said Anastasia quietly. Sonia and Portia switched on spotlights attached to the barrels of their boltguns, picking out areas of detail in the dark. Immediately, they could see that something was very wrong.

The cargo bay seemed to be filled with a huge mass of lattices of some sort, made from a black, oily-looking substance. A few metres were clear around the entry port, then all vision was blocked by the things. Looking up, Anastasia saw the structures bend inwards, blocking the view to the roof of the cargo bay. There seemed to be shapes built into the things, but they were indistinct. Something caught her eye in the mass, and she took a step closer to it.

"What happened here," she whispered, her voice carrying a touch of horror. The shape she had seen had been human, but it had been somehow half-absorbed by the alien structure, and seemed to be in the process of being digested. What remained of its chest still shifted slightly, drawing shallow breaths. The head had been mostly covered by the thing it was embedded in, but the mouth remained exposed, open in a silent scream.

"Sister Superior," said Sonia, her voice sharp. Anastasia looked around to see the Sister's spotlight centred on a patch of structure less than a dozen metres away. She looked at the shape, squinting or a moment, then she saw it. The creature was curled into a ball, its razor claws wrapped tightly around its body, but it was still recognisable. Even as she watched, a small patch of the slimy material dissolved to leave the hormagaunt's chest exposed.

"Airlock," Anastasia whispered. She backed slowly away from the structures, sensing her crew behind her. There was a noise from above her, just as she reached the entry port, and she looked up into the eyes of something that had been human. The body was suspended upside-down, its head hanging free. Its mouth opened and closed, trying to form words, but no sound emerged. They weren't necessary: its eyes spoke clearly enough.

There was the whoosh of the flamer from outside the entry port, and noises from further inside the cargo bay. Anastasia looked back down, her bolt pistol rising and firing upwards into the poor thing's head. She tossed an incendiary grenade into the alien forest and ducked through the port, slapping the door control hard. She heard the grenade explode, saw a flash as the door closed, and heard a thump as something hurled itself against it. Sonia and Portia were firing their boltguns at dim shapes trying to advance through a section of corridor that was burning fiercely. Anastasia motioned them back, and led the way back towards the elevator.

Halfway up the elevator shaft, a claw ripped through the floor. Sonia fired back down through the hole, and a screech echoed back up, disappearing downwards. Anastasia fired through the roof as more claws started tearing their way in from above. The elevator shuddered to a halt.

"Seal," yelled the Sister Superior over the noise of the aliens and her crew's weapons. She saw all three helmets snap into place, then activated her own. She then pulled Zoey away from the far wall and clamped a krak grenade to it. "Cover!" she added. All four immediately crouched, turning their armoured backs to the far wall. The explosion ripped through the wall of the elevator, hurling shrapnel at its occupants. There was a brief roar as the elevator's air escaped into the vacuum outside, then everything went silent.

"Magnetic clamps," said Anastasia through the armour's communication link, as she led her crew out through the jagged hole in the elevator shaft. She caught a glimpse of something moving into the abandoned elevator, then they were moving over the hull of the giant freighter as fast as they could. Anastasia unclipped her auspex from her armour and handed it to Portia. "Remote undock, and bring the ship around," she said. Portia nodded and concentrated on the auspex, handing her boltgun to Zoey, replacing her flamer.

The creatures were visible behind them now, moving surprisingly quickly through the vacuum. Their claws tore jagged gashes in the outer layers of the ship's hull as they pulled themselves forward. After sprinting ahead a few metres, Zoey and Sonia braced themselves against the hull and fired a hail of bolt shells into the pursuing creatures. The blasts tore apart a few, and sent several more spinning away from the hull, but there were more to take their place, emerging through a surreal shifting cloud of their predecessors' vital fluids. They seemed to be becoming accustomed to their new environment, and Anastasia saw several taking long bounding leaps, skimming effortlessly along the hull for several seconds before digging their claws in again and changing direction. The closest ones were nearly on top of them.

"Sisters," rang Sonia's voice through the helmet link. Anastasia turned to see the Sister firing into a mass of hormagaunts emerging from a jagged tear in the hull ahead of them. The four warriors were almost back-to-back, their enemy closing in from all sides. Anastasia braced herself against the recoil and fired her pistol, blasting apart the head of a creature that had launched itself towards them. There seemed to be no end to the things.

A shadow fell over them, and Anastasia turned to see the light of the closest star being blocked by the dull grey hull of the Centaur. A panel slid open underneath its nose, and a pair of cannons dropped out, swivelling and firing into the hormagaunts. The creatures were torn apart and thrown away from the hull in a tangle of limbs and blood. Anastasia turned and fired more shells into the creatures behind her, as the turret guns began to fire on them as well. Under the covering hail of firepower, the four Sisters made their way to the safety of their ship.