For a fleeting instant, Zahariel thought his overtaxed nerves were misfiring, playing tricks on him. But then one of the dead Jaegers drew back his arms and pushed himself clumsily upright, revealing the ghastly wounds that covered his torso and neck. The dead soldier's face was slack, his mouth agape and his eyes glowing an unearthly green.

Another corpse stirred, and another, until the entire mound was lurching into motion. Beneath the Jaegers were the bloated, rotting corpses of men and women in grey worker's coveralls, their slime-covered faces contorted in expressions of agony or horror. They were covered in patches of mould and colonies of squirming maggots; many were missing patches of skin or bore stumps of splintered bone in place of limbs. Yet what these horrors had concealed beneath their rotting bulk was more terrible by far.

As the hundreds of corpses began to shamble, stagger and crawl towards the stunned Astartes, they exposed a score of bloated, squirming larvae that once had been people. Their bones had softened and their muscles stretched until their shapes bore little resemblance to human beings; only their feebly contorting limbs and their distorted, agonised faces revealed what they once had been. Zahariel could clearly see the coiled, black shapes of reaver worms curled within the jelly-like torsos of the larvae, slowly feeding on the still-living bodies of their hosts as they grew to maturity.

The larvae recoiled from the open air, vainly trying to squirm beneath the armoured coils of the enormous worm that had lain at the centre of the chamber's sorcerous spiral. Daubed with blasphemous runes and glistening with slime, the worm queen raised her massive skull and screeched its fury at the grubs that had invaded its domain.

It was a sight that would have broken the courage of lesser men, but hard discipline and the bonds of brotherhood held the Astartes in place. Chapter Master Astelan took a couple of steps forward and stood by Zahariel's side. 'What are your orders?' he asked in a steely voice, as the horde of living dead approached.

Zahariel called upon the rotes Israfael had taught him and mastered the pounding agony in his skull before it could overwhelm him.

'Form a firing line!' he ordered.

The closest of the corpses was only five metres away. As the eight remaining Astartes rushed forward to stand shoulder-to-shoulder beside Zahariel and Astelan, the Librarian called out. 'Change magazines!'

As one, nine pairs of hands went to work, releasing nearly-empty clips from their bolt pistols and slapping fresh ones home. Charging handles racked home with a well-oiled clatter.

The shambling mob was two metres away, almost close enough to touch. 'Squad!' Zahariel yelled. 'One step back! Five rounds rapid. Fire!'

In lockstep, ten pairs of boots crashed upon the permacrete. Bolt pistols barked in a rolling volley. Green clad bodies jerked and blew apart in the storm of mass-reactive rounds. The first rank of corpses disintegrated under the fusillade.

'One step back. Five rounds rapid. Fire!'

The bolt pistols thundered again. Each round found its mark, and fifty more bodies were reduced to bloody fragments. The rest of the mob staggered on, their outstretched hands little more than a metre away.

At Zahariel's command, the squad took one last step back and fired five more rounds into the press. Firing bolts locked back on empty magazines as fifty more bodies erupted into gory mist. The mob had been cut in half in the span of twenty seconds, but the remainder pressed their advance.

Wreathed in propellant smoke, Zahariel raised his crackling staff. 'Loyalty and honour!' he roared. 'Charge!'

With a furious shout, the Dark Angels leapt into the midst of the monstrosities, their chain-blades howling. Swung with superhuman strength, the swords split torsos and severed limbs with each blurring stroke. Corpses toppled at the touch of Zahariel's force staff, their rotting flesh sizzling under the lash of the Librarian's psychic power.

The undead surrounded the grimly fighting Astartes, clawing and grabbing at their armoured forms. What they lacked in strength and skill they sought to make up for in numbers, but the Dark Angels were masters at the craft of slaughter, and their ranks melted away like ice on a hot iron. Within moments the tide turned inexorably in the Astartes' favour - and then the worm queen struck.

A timely flash of lightning provided the only warning. The fickle light sizzled about the thermal core, and Zahariel saw the bulk of the great worm rearing up, like a snake about to strike. The Librarian hurled himself to the side just as the creature lunged into the squad's midst with the force of a runaway train.

With a shout, Zahariel spun to face the beast as the queen gathered herself together like a coiling spring and lashed out again, this time catching Gideon and two of the corpses in its wide mandibles. The curved pincers snapped shut like a giant scissors. The two corpses were bisected at once; Gideon's armour resisted a half-second longer before giving way as well.

Astelan and Jonas whirled on their heels and slashed furiously at the queen, but their chainswords left little more than shallow scars on the worm's thick armoured plates. Screeching in rage, the queen tossed her bony head and smashed Jonas aside, then lunged at Astelan with her bloody mandibles. The chapter master leapt aside at the last moment, hacking a divot out of one of the huge pincers before rolling nimbly away. The worm crushed another half-dozen corpses beneath its bulk as it drew its coils together for another leap. Three Astartes charged the monster from different directions, hacking at it with powerful blows that left only scratches on the worm's thick, black armour. One of the Dark Angels lingered within reach a moment too long and was struck from behind by the queen's lashing tail. The huge warrior was flipped head-over-heels by the powerful blow and landed heavily on his face. A bolt pistol barked; Gideon, lying in a pool of his own blood, had reloaded his weapon and was snapping careful shots at the worm's eyes. Two burst apart in a shower of ichor, causing the queen to thrash and shriek in pain, but the wounds didn't seem to slow the creature in the slightest.

Zahariel dropped his empty pistol and took a two-handed grip on his force staff. He had to end the fight quickly, before the monster killed or crippled any more of his squad. The Librarian channelled his will into the psycho-reactive matrices embedded in the force weapon's staff. Crackling arcs of violet light wound around the metal haft and created a blazing halo about the double-headed eagle at the staffs head. Raising the weapon above his head, Zahariel shouted a wild oath and charged straight at the creature.

The movement and the flickering light of the staff had the desired effect. The worm queen swung its bleeding head around and lunged at Zahariel, smashing into the Librarian in mid-charge.

The impact was tremendous, overwhelming Zahariel's senses. One moment he was racing towards the creature and the next he was flat on his back with the worm's mandibles locked about his waist. A score of flashing crimson runes blinked at the corners of his vision, warning of extensive servomotor damage and armour breaches. His vision came and went in bursts of distortion as the creature's scissor-like pincers cut into the feeds running from the power unit on his back. He heard the groan and pop of ceramite plates giving way beneath the terrible force of the worm's mandibles. He saw his battered armour reflected in the myriad facets of four black, soulless eyes, each as large as a dinner plate and close enough to touch.

Zahariel brought down the butt of his crackling staff on the queen's skull, right between its monstrous eyes.

The force staff punched through the thick bone with a flash of blue-white light and an angry clap of thunder as the Librarian channelled every erg of psychic force he could command into the creature's body. Nerves fried and brain matter boiled; the worm's remaining eyes burst and its armour plates cracked as steam erupted from its core. Zahariel snuffed out the monster's life force in a split second with the raging winds of the warp itself. It let out a rending shriek and tossed its head in a death spasm, smashing Zahariel to the ground hard enough to knock him unconscious.