Another warrior fell, dragged down by alien claws and Learchus felt the spirit of the martyr move within him. As he hacked down another hissing beast, he began to sing, a rousing hymnal from the dawn of the Imperium, a battle song to stir the hearts of all who heard it.

Astador joined him and soon every one of the Space Marines was raising their voices to the heavens in praise of the Emperor as the tyranids closed in for the kill.

Pasanius kicked the guardian beast in the face, crushing its skull and pulverising its brain as Henghast finally drove his sword through its guts. Its claws spasmed and released him. He fell to the floor with a splash.

Uriel saw the golden hilt of his sword protruding from the corpse of the warrior organism. He struggled to his feet to reach it, wishing no more than to die on his feet with a weapon in his hand. He wrenched it from the dissolving flesh of the beast and limped to stand beside Pasanius and the gore-streaked Damias and Henghast.

The four Space Marines stood with their weapons facing outwards, ready to fight and die like men. Hissing creatures closed in on them, fangs bared and claws poised to strike.

A sudden, violent tremor shook the chamber and a tormented, animal wail built from behind Uriel. The smaller creatures dropped to their haunches in terror as the throat of the Norn Queen, silent for hundreds of years, gave voice to a screech of unimaginable pain.

Its body convulsed, tearing free of its egg sac and mucus-hardened limbs fused to the walls broke with the violence of the spasms. Huge tears in the queen's belly ripped open, mutant growths erupting from every one. The queen's flesh boiled and ripped as her evolutionary genome was thrown into anarchy and stimulated beyond all control by Magos Locard's gene-poison.

Every creature in the chamber took up the wailing screech of agony as evolutionary imperatives were passed through the gestalt consciousness which linked every creature in the hive ship and every creature connected to the overmind.

The chamber shook, the very structure of the ship screaming as every creature was driven into a frenzy of uncontrolled mutation.

Uriel watched as creatures convulsed so violently they snapped their own spines, frothing at the mouth with aberrant growths and genetic deviancy.

'It's working!' shouted Uriel as portions of the chamber erupted in white-hot fluids and acidic slime fell from the ceiling in enormous clumps.

'Aye, it worked,' agreed Pasanius, cradling his mangled arm, 'but let's get out of here before it claims us as well.'

The Space Marines fought their way through the rapidly disintegrating chamber of the Norn Queen, the aliens jerking spastically as they died.

Uriel felt a tremendous sense of vindication as they fled the chamber, knowing that he had made the right choice to lead this mission.

He never saw the javelin-like spine shoot from the carapace of the Norn Queen as it slashed through the collapsing cavern. The two-metre barb hammered through his back and exploded from his stomach in an explosion of ceramite and flesh.

The jagged missile passed clean through him, juddering in the necrotising floor.

He slumped forward, the pain beyond anything he had ever felt before.

'Uriel!' screamed Pasanius.

He looked down at the wound. Strange that there was no blood. A hard red scab formed around the exit wound, but there was no blood. A sluggish feeling permeated his body and a sharp pain blossomed in his left side, spreading throughout his body.

Pasanius lifted him from the ground.

'Damias, you're an Apothecary! Help him!'

Uriel felt his vision grey, his limbs becoming heavier and heavier.

He couldn't understand. He'd been hurt worse than this before and not felt like this. He saw his heart rate spiralling downwards in the corner of his visor.

'Bones of Corax,' swore Damias. 'It's phage-cell poisoning. It's sending his Larraman cells into overdrive and his blood is clotting throughout his body!'

'Then do something about it!' bellowed Pasanius.

Uriel felt their words fading and tried to open his mouth, but his vision greyed and he felt his hearts stop pumping as they clogged with coagulated blood.

He closed his eyes and the pain went away.

Learchus killed another tyranid creature and started another verse before he realised that the attacks were not coming with the same fury as before.

In fact, they were not coming at all.

The alien beasts thrashed in violent fits, their screeching roars rising to new heights. He saw packs of creatures turn on one another, slashing each other's bodies to red ruin without cease. Thrashing monsters filled the plaza, howling in pain as the overmind died, their bodies unable to survive the psychic Shockwave of its death.

Tyranid organisms scuttled and ran through the streets of District Quintus, howling in berserk fury and falling on one another in an orgy of senseless bloodletting.

The Space Marines forgotten, the tyranids tore themselves to pieces.

Before any of the larger creatures were able to regain control, the sixteen surviving Space Marines made their way towards the wall of District Sextos. Very few creatures opposed them and those that did attacked with no cohesion or purpose and were butchered without mercy.

The internecine slaughter continued throughout the rest of the day, the defenders watching with elation as the alien menace that had threatened their world for so long tore itself to pieces.

As night drew in and the temperatures plummeted, whole swathes of organisms perished as they succumbed to the freezing temperatures, unable to seek shelter without the control of the hive mind to direct them.

Some creatures survived, larger creatures with a degree of autonomy from the hive mind, and soon they accumulated small packs of desperate beasts, taking refuge in the warmer parts of the ruined city.

Night finally closed on Tarsis Ultra as a speck of light descended from the heavens, a battered Space Marine gun-ship, its wings dipped in mourning.

EPILOGUE

Pasanius sat alone on the ruins of the District Quintus wall, staring out into the white expanse of the plain before the devastated city. Stripped of his armour, he wore a simple chiton of blue cloth and cradled his silver arm close to his chest. He watched as a transport flashed overhead: returning from another ruined city with more bad news no doubt.

It had been six days since their return from the dying hive ship and Pasanius had spent much of his time in prayer, offering his thanks for their victory and his sorrows for those who had fallen in battle. There were so many dead, so many prayers to say. The vast chamber of the mosaic held a candle for every soldier dead or missing, and the glowing light from the crystal dome was visible from the far end of the valley.

Among the honoured dead was Sebastien Montante, his spine-pierced body discovered on the ruins of the very wall Pasanius now sat upon. His body lay in state in the Imperial palace and the priests of this world were already calling for his beatification. Pasanius knew it probably wouldn't be long before Sebastien was made into a saint and he chuckled, thinking how amusing the Fabricator Marshal would have found that idea. Saint Sebastien, it had a nice ring to it.

Colonel Stagler's body had been found by his men atop a mound of tyranid creatures, his frozen corpse brutally hacked to pieces. His men did not mourn him. He had died in the Krieg way and that was enough. With both Stagler and Rabelaq dead, Major Aries Satria of the Erebus Defence Legion assumed control of the Imperial Guard forces until such time as a more senior Guard officer could be appointed.