'Atrocity? Is that what we're calling it now?'

'What else would you call it? Astartes warriors have committed murder.'

The enormity of what Varvarus was suggesting staggered Maloghurst, and he lowered himself slowly into one of the chairs at the Warmaster's table.

'You would have me give up an Astartes warrior for this? I cannot do it.'

Varvarus leaned over the table, the decorations and medals of his dress uniform reflecting like gold suns in its black surface.

'Innocent blood has been spilled, and while I can understand the reasons behind the actions of your men, it changes nothing.'

'I can't do it, Hektor,' said Maloghurst, shaking his head.

Varvarus moved to stand next to him. 'You and I both swore the oath of loyalty to the Imperium did we not?'

'We did, but what has that to do with anything?'

The old general locked eyes with Maloghurst and said, 'We swore that we would uphold the ideals of nobility and justice that the Imperium stands for, yes?'

'Yes, but this is different. There were extenuating circumstances…'

'Irrelevant,' snapped Varvarus. 'The Imperium must stand for something, or it stands for nothing. If you turn away from this, then you betray that oath of loyalty. Axe you willing to do that, Maloghurst?'

Before he could answer, there was a soft knocking on the glass of the sanctum and Maloghurst turned to see who disturbed them.

Ing Mae Sing, Mistress of Astropathy, stood before them like a skeletal ghost in a hooded white robe, the upper portions of her face shrouded in shadows.

'Mistress Sing,' said Varvarus, bowing deeply towards the telepath.

'Lord Varvarus,' she replied, her voice soft and feather-light. She returned the lord commander's bow and despite her blindness, inclined her head in precisely the right direction - a talent that never failed to unnerve Maloghurst.

'What is it, Mistress Sing?' he asked, though in truth, he was glad of the interruption.

'I bring tidings that must concern you, Sire Maloghurst,' she said, turning her blind gaze upon him. 'The astropathic choirs are unsettled. They sense a powerful surge in the currents of the warp: powerful and growing.'

'What does that mean?' he asked.

'That the veil between worlds grows thin,' said Ing Mae Sing.

Stripped out of his armour and wearing bloody surgical robes, Vaddon was as close to desperate as he had ever been in his long experience as an apothecary of the Sons of Horus. The Warmaster lay before him on the gurney, his flesh exposed to his knives and to the probes of the medicae machines. Oxygen was fed to the Warmaster through a mask, and saline drips pumped fluids into his body in an attempt to normalise his blood pressure. Medicae servitors brought fresh blood for immediate transfusions and the entire theatre fizzed with tension and frantic activity.

'We're losing him!' shouted Apothecary Logaan, watching the heart monitors. 'Blood pressure is dropping rapidly, heart rate spiking. He's going to arrest!'

'Damn it,' cursed Vaddon. 'Get me more Larraman serum, his blood won't clot, and fix up another fluid line.'

A whirring surgical narthecium swung down from the ceiling, multiple limbs clattering as they obeyed Vaddon's shouted commands. Fresh Larraman cells were pumped directly into Horus's shoulder and the bleeding slowed, though Vaddon could see it still wasn't stopping completely. Thick needles jabbed into the Warmaster's arms, filling him with super-oxygenated blood, but their supply was dwindling faster than he would have believed possible.

'Stabilising,' breathed Logaan. 'Heart rate slowing and blood pressure is up.'

'Good,' said Vaddon. 'We've got some breathing room then.'

'He can't take much more of this,' said Logaan. 'We're running out of things we can do for him.'

'I'll not hear that in my theatre, Logaan,' snapped Vaddon. 'We're not going to lose him.'

The Warmaster's chest hiked as he clung to life, his breathing coming in short, hyperventilating gasps, more blood pumping from the wound in his shoulder.

Of the two wounds the Warmaster had suffered, it seemed the least severe, but Vaddon knew it was the one that was killing him. The puncture wound in his chest had practically healed already, ultra sonograms showing that his lung had sealed itself off from the pulmonary system while it repaired itself. The Warmaster's secondary lungs were sustaining him for now.

The Mournival hovered like expectant fathers as the apothecaries worked harder than they had ever worked before. Vaddon had never expected to have the Warmaster for a patient. The primarch's biology was as far beyond that of a normal Astartes warrior as his own was from a mortal man, and Vaddon knew that he was out of his depth. Only the Emperor himself had the knowledge to delve into the body of a primarch with confidence, and the enormity of what was occurring was not lost on him. A green light winked into life on the narthecium machine and he lifted the data-slate from the port in its silver steel surface. Numbers and text scrolled across its glossy surface and though much of it made no sense to him, he felt his spirits fall as what he could comprehend sank in.

Seeing that the Warmaster was stable, he circled the operating slab and joined the Mournival, wishing he had better news for them.

'What's wrong with him?' demanded Abaddon. 'Why is he still lying there?'

'Honestly, first captain, I don't know.'

'What do you mean, "You don't know"?' shouted Abaddon, grabbing Vaddon and slamming him against the theatre wall. Silver trays laden with scalpels, saws and forceps clattered to the tiled floor. 'Why don't you know?'

Loken and Aximand grappled with the first captain as Vaddon felt Abaddon's enormous strength slowly crushing his neck.

'Let go of him, Ezekyle!' cried Loken. 'This isn't helping!'

'You won't let him die!' snarled Abaddon, and Vaddon was amazed to see a terrible fear in the first captain's eyes. 'He is the Warmaster!'

'You think I don't know that?' gasped Vaddon as the others prised Abaddon's grip from his neck. He slid down the wall, already able to feel the swelling in his bruised throat.

'Emperor damn you if you let him die,' hissed Abaddon, stalking the theatre with predatory strides. 'If he dies, I will kill you.'

Aximand led the first captain away from him, speaking soothing words as Loken and Torgaddon helped him to his feet.

'The man's a maniac,' hissed Vaddon. 'Get him out of my theatre, now!'

'He's not himself, apothecary,' explained Loken. 'None of us are.'

'Just keep him away from my team, captain,' warned Vaddon. 'He's not in control of himself, and that makes him dangerous.'

'We will,' Torgaddon promised him. 'Now what can you tell us? Will he survive?'

Vaddon took a moment to compose himself before answering, picking up his fallen data-slate. 'As I said before, I just don't know. We're like children trying to repair a logic engine that's been dropped from orbit. We don't understand even a fraction of what his body is capable of or how it works. I can't even begin to guess what kind of damage it's suffered to have caused this'

'What's actually happening to him?' asked Loken.

'It's the wound in his shoulder; it won't clot. It's bleeding out and we can't stop it. We found some degraded genetic residue in the wound that might be some kind of poison, but I can't be sure.'

'Might it be a bacteriological or a viral infection?' asked Torgaddon. 'The water on Davin's moon was thick with contaminants. I ought to know, I swallowed a flagon's worth of it.'

'No,' said Vaddon. 'The Warmaster's body is, for all intents and purposes, immune to such things'