Decius spoke in an awed whisper. 'It... it is incredible. The power of such destruction...'

Garro felt unsteady and held out a hand, placing it on the thick armourglass of the gallery window. 'It is not over yet. There is one more strike to come before this killing is complete.'

'But the virus, it is consuming the whole planet... all life, everywhere! What other devastation can the Warmaster turn upon it?'

Garro's words were weary and hollow. "With so many dead, so fast, the Life-Easter bums out quickly, but the mass of corpses it leaves behind moulder and rot' His face soured. The... remains turn to gaseous putrefaction and decay. Imagine it, Solun, a whole world turned into a gigantic charnel house, the very atmosphere stinking and choked with the stench of new death.'

Out in the fleet, the ships were shifting, the formation parting so that a single vessel could move into a

pre-determined firing position. It was the Warmaster's flagship, the bright sword-blade shape of the Vengeful Spirit.

'Of course,' Garro said bitterly, 'Horus. He comes to make the killing shot himself. I should have expected no less.' Garro wanted to close his eyes, to look away, but everywhere he turned his gaze he was haunted by the faces of the men that he had left alone down there. He saw Temeter and Tarvitz, imagined them dying in the onslaught, hoping, even praying that they might have survived the first wave. 'Now they must survive the final blow.'

The Vengeful Spirit drifted to a halt and turned with stately menace to point her bow down at Isstvan III. In the silence, there was a flicker of light from the maws of the warship's twin lance cannons along the flanks of the hull. The bolts of blinding fire touched the atmospheric envelope of the planet and a new colour bloomed among the blackened clouds: the searing orange of a firestorm.

'A match to tinder/ breathed Decius. The fumes from the decayed dead are lit. The flames will burn across the world.'

'All by the hand of Horus,' said Garro, fighting off the sickness in his heart.

They stood there for what seemed like hours, watching the fires cross continents and raze cities as the Warmaster's flagship orbited above it all, the lone arbiter of Isstvan Ill's destruction. Time fell away as the two Astartes stood witness to the distant slaughter.

At last, a loud chime sounded through the chamber over the frigate's inter-craft vox net and shattered the silence. 'Captain Garro to the bridge.' It was Carya's voice, low and toneless. 'We have a problem.'

Nathaniel finally turned from the windows and walked away. Decius remained a few moments, his eyes glittering, before he followed suit, running to keep up with his commander.

BARYK CARYA COULDN'T bring himself to look out of the bridge's forward viewports. The slow death of the planet below was abhorrent to him, a brutal act that went against every fibre of his being. He had not taken an oath of fealty to be part of such horror. He scanned the chamber and found Maas glaring at him from the vox alcove, still gripping the message slip the shipmaster had given him. He advanced towards the junior officer, working to maintain his outward mask of authority. 'Is it done?' he demanded.

'I...' Maas grimaced. 'I have sent the signal you ordered me to send, sir.'

The young man's displeasure was clear on his face, although Carya could have cared less for his unwillingness to broadcast what was an outright lie. The master snatched the paper from his grip and shredded it between his fingers. The message had gone to Terminus Est with Grulgor's command rune carefully forged by Vought. In terse phrases that he hoped would emulate the speech of an Astartes, Carya had informed First Captain Typhon that Eisenstein had suffered a weapons malfunction that prevented it firing on Isstvan III. It was a poor ruse, as thin as the paper he had scribbled it on, but it would buy them time.

'What you have done will cost you your rank/ hissed Maas in a sullen voice. 'You are upon the verge of open mutiny against the Warmaster's command!'

'Get your terms straight, boy/ retorted Carya. 'Mutiny is when the enlisted men take over a vessel. When the ship's master does it, it's called barratry.'

'Whatever name you give it, it is wrong!'

'Wrong?' Carya's anger went white-hot in an instant, and he grabbed Maas by the scruff of the neck, dragging him from the alcove and across the bridge. 'Do you want to see wrong, boy? Look at that!' He forced the vox officer's face towards the viewports and the distant carnage. He gave him a half-hearted shove. 'Get back to your damn station, and keep your thoughts to yourself!'

Vought came to his side. 'Sir, your pardon? The other ship, I have confirmed it. It's on an approach vector at full military thrust.'

'Within gun range?'

She nodded. 'I've taken the liberty of getting a firing solution, although that earlier trick won't work this time. If we kill it, the whole fleet will see.'

The bridge hatch irised open and the commander of the Seventh Company entered with one of his men, his eyes hollow. 'Shipmaster,' said Garro gravely, 'is there a matter of urgency?'

He nodded. 'There is. Racel, show him.'

Vought manipulated the controls on the hololith to display a close-range globe of space around the frigate. A red arrowhead was moving steadily towards the vessel. 'Another Thunderhawk,' she explained, 'on an intercept vector.'

'Tarvitz?' asked the other Astartes, the one called Decius. 'Has he been in orbit all this time, or returned from the surface?'

Racel shook her head. 'No, this ship's idem codes are different. The designation is Nine Delta. It belongs to the Sons of Horus, assigned aboard the Vengeful Spirit!

'He knows,' said the vox officer. 'Horus knows what happened here. He's coming to-'

'Shut up, Maas!' snapped Carya.

'He could be right/ said Decius.

Garro ignored the hololith and went to the viewport, searching for the transport with his own eyes. After a moment he pointed. 'There, I see it.'

'Captain, what are your orders?' The shipmaster shifted uncomfortably, perturbed by the strange sensation of events repeating themselves. This was how it had all begun, with a lone Thunderhawk, with Tarvitz and his warning.

Some emotion Carya couldn't identify crossed Garro's face like a cloud passing before the sun. Then he turned on his heel and marched to the communications panel. Without preamble he snatched up the vox pickup and spoke into it. 'Thunderhawk gunship, identify yourself Garro glanced back at Vought and threw her a look that said be ready.

A throaty voice thick with a Cthonian accent growled from the speaker. 'My name is Iacton Qruze, formerly of the Sons of Horus.'

'Formerly?' repeated Garro.

'Yes, formerly.'

Decius nodded to his commander. 'I know of this one, sir, an old campaigner, past his time, the third captain under Horus. They call him "the Half-Heard".'

Garro took this without comment. 'Explain yourself,' he demanded. Carya found that his hands were tight, his knuckles bloodless with the tension.

He heard the agony beneath the veteran's next words, even through the crackling hiss of the vox channel. 'I am no longer part of the Legion. I can no longer be a party to what the Warmaster is doing.'

The battle-captain held the vox away and rubbed at his face.

'It could be a rase/ insisted Vought. 'That transport could be packed with Astartes from Horus's ship!'

'Let them come/ growled Decius. 'I would prefer honest battle to all this subterfuge.'

'Or perhaps a bomb

'No.' Garro's voice brought silence. 'She is aboard. He does not lie.'

She? Carya's brow furrowed. Who is he talking about?

'There are refugees on that vessel, I am certain of it. Open the landing bay and prepare to take the Thun-derhawk aboard,' he ordered.