Tarvitz hurried towards the makeshift strongpoint at its centre, the battlements formed from carved up bodies heaped between the battered forms of fallen drop-pods.

A World Eater with blood-soaked armour and a scarred face nodded to him as he climbed the

gruesome ramp of bodies. The warrior's armour was so drenched in blood that Tarvitz wondered for a moment why he hadn't just painted himself red to begin with. 'Captain Ehrlen,’ said Tarvitz. ^Vhere is he?' The warrior wasted no breath on words and simply jerked a thumb in the direction of a warrior with dozens of fluttering oath papers hanging from his breastplate. Tarvitz nodded his thanks and set off through the sttongpoint. He passed wounded Astartes who were tended by an apothecary who looked as if he had fought as hard as any of his patients. Beside him lay two fallen World Eaters, their bodies unceremoniously dumped out of the way.

Ehrlen looked up as Tarvitz approached. The captain's face had been badly burned in some previous battle and his axe was clotted with so much blood that it better resembled a club.

'Looks like the Emperor's Children have sent us reinforcements!' shouted Ehrlen, to grunts of laughter from his fellow World Eaters. 'One whole warrior! We are blessed, the enemy will run away for sure.'

'Captain,’ said Tarvitz, joining Ehrlen at the barricade of Isstvanian dead. 'My name is Captain Saul Tarvitz and I'm here to warn you that you have to get your squads into cover,’

'Into cover? Unacceptable,’ said Ehrlen, nodding towards the far side of the plaza. Shapes moved in their windows and between the mansions. They're regrouping. If we move now they will overwhelm us.'

'The Isstvanians have a bio-weapon,’ said Tarvitz, knowing a lie was the only way to convince the World Eaters. 'They're going to fire it. It'll kill everyone and everything in the Choral City,’

They're going to destroy their own capital? I thought this place was some kind of church? Holy to them?'

They've shown how much they value their own,’ replied Tarvitz quickly, indicating the heaps of dead in front of them. They'll sacrifice this city to kill us. Driving us from their planet is worth more to them than this city,’

'So you would have us abandon this position?' demanded Ehrlen, as if Tarvitz had personally insulted his honour. 'How do you know all this?'

'I just got here from orbit. The weapon has already been unleashed. If you're above ground when the virus strike hits you will die. If you believe nothing else, believe that,’ Then where do you suggest we move to?' 'Just to the west of this position, captain,’ said Tarvitz, stealing a glance at the sky. The edge of the trench system is thick with bunkers, blast proof shelters. If you get your men into them, they should be safe,’

'Should be?' snapped Ehrlen. 'That's the best you can offer me?'

Ehrlen stared at Tarvitz for a moment. 'If you are wrong the blood of my warriors will be on your hands and I will kill you for their deaths,’

'I understand that, captain,’ urged Tarvitz, 'but we don't have much time.'

Very well, Captain Tarvitz,' said Ehrlen. 'Sergeant Fleiste, left flank! Sergeant Wronde, right! World Eaters, general advance to the west, blades out!'

The World Eaters drew their chainaxes and swords. The bloodstained assault units hurried to the front and stepped over the makeshift barricades of corpses.

'Are you coming, Tarvitz?' asked Ehrlen.

Tarvitz nodded, drawing his broadsword and following the World Eaters into the plaza.

Although they were fellow Astartes, he knew he was a stranger among them as they ran, spitting battle curses and splashing through the dead towards the potential safety of the bunkers.

Tarvitz glanced up at the gathering clouds and felt his chest tighten.

The first burning streaks were falling towards the

city.

IT'S STARTED,' SAID Loken.

Lachost looked up from the field vox. Fire was streaking through the sky towards the Choral City. Loken tried to judge the angle and speed of the falling darts of fire - some of them would come down between the spires of the Sirenhold, just like the Sons of Horus's own drop-pods had done hours earlier, and they would hit in a matter of minutes.

'Did Lucius say anything else?'

'No,’ said Lachost. 'Some bio-weapon. That was all. It sounded like he ran into a fire fight.'

Tarik,’ shouted Loken. 'We need to get into cover, now. Beneath the Sirenhold,’

'Will that be enough?'

'If they dug their catacombs deep enough, then maybe,’

'And if not?'

'From what Lucius said, we'll die,’

'Then we'd better get a move on,’

Loken turned to the Sons of Horns advancing around him. 'Incoming! Get to the Sirenhold and head down! Now!'

The closest spire of the Sirenhold was a towering monstrosity of grotesque writhing figures and leering gargoyle faces, a vision taken from some ancient hell of Isstvan's myths. The Sons of Horas broke their advance formation and ran towards it.

Loken heard the distinctive boom of an airborne detonation high above the city and pushed himself harder as he entered the darkness of the tomb-spire. Inside, it was dark and ugly, the floor paved with tortured, half-human figures who reached up with stone hands, as if through the bars of a cage.

There's a way down,’ said Torgaddon. Loken followed as Astartes ran towards the catacomb entrance, a huge monstrous stone head with a passageway leading down its throat.

As the darkness closed around him, Loken heard a familiar sound drifting from beyond the walls of the Sirenhold.

It was screaming.

It was the song of the Choral City's death.

THE FIRST VIRUS bombs detonated high above the Choral City, the huge explosions spreading the deadly payloads far and wide into the atmosphere. Designed to kill every living thing on the surface of a planet, the viral strains released on Isstvan Щ were the most efficient killers in the Warmaster's arsenal. The bombs had a high enough yield to murder the planet a hundred times over and were set to burst at numerous differing altitudes and locations across the surface of the planet.

The virus leapt through forests and plains, sweeping along algal blooms and riding air currents across the globe. It crossed mountains, forded rivers, burrowed through glaciers. The Imperium's deadliest weapons, the Emperor himself had been loath to use them.

The bombs fell all across Isstvan III, but most of all, they fell on the Choral City.

THE WORLD EATERS were the furthest from cover and suffered the worst of the initial bombardment. Some had reached the safety of the bunkers, but many more had not. Warriors fell to their knees as the virus penetrated their armoured bodies, deadly corrosive agents laced into the viral structure of the weapons dissolving exposed pipes and armour joints, or finding their way inside through battle damage.

Astartes screamed. The sound was all the more shocking for its very existence rather than for the horror of its tone. The virus broke down cellular bonds at the molecular level and its victims literally dissolved into a soup of rancid meat within minutes of exposure, leaving little but sloshing suits of rotted armour. Even many of those who reached the safety of the sealed bunkers died in agony as they shut the doors only to find they had brought the lethal virus inside with them.

The virus spread through the civilian populace of Isstvan III at the speed of thought, leaping from victim to victim in the time it took to breathe in its foul contagion. People dropped where they stood, the flesh sloughing from their skeletons as their nervous systems collapsed and their bones turned to the consistency of jelly.

Bright explosions fed the viral feast, perpetuating the fatal reactions of corruption. The very lethality of the virus was its own worst enemy, for without a host organism to carry it from victim to victim, the virus quickly consumed itself.