A third lashed out at Praetor, but the chainblade it wielded ran afoul of the sergeant’s sturdy armour. Broken metal teeth rattled the deck, followed swiftly by the Raptor’s sundered corpse.

Tsu’gan came face-to-face with the lone survivor, their leader and the one who wore the daemon’s distended face. It angled its head, fibre bundle cabling at its neck sparked as its body spasmed. Then the wretched, avian creature screeched at him. The goad forced Tsu’gan to swing – he wanted to feel its flesh and bone churning against his chainfist – but the Raptor leader had banked on this and avoided the blow, snatching up the fallen meltagun instead.

It looked like it was about to turn the weapon against the Firedrake before the creature boosted its jump jets and soared into the vaulted ceiling, burning through metal sheeting as it went, fashioning an escape route. Tsu’gan’s bulk blocked a clear shot for the others and storm bolter rounds tore up the pipes above harmlessly before the Firedrakes were alone again.

‘Night Lords,’ spat Tsu’gan. ‘Craven whelps and molesters. What are they doing aboard the Protean?’

Praetor couldn’t answer. He was listening to the comm-feed.

‘Nu’mean is in trouble,’ he said when he was done. ‘The Traitors will have to wait–’

Tsu’gan bristled. ‘Hrydor’s vengeance!’

‘Will have to wait,’ Praetor repeated firmly. ‘Our brothers, those who yet live and breathe, need us to breach the central power room now.’

They were about to retrace their steps when an explosion, loud enough to resonate through Tsu’gan’s armour, rocked the corridor. Metal debris fell in thick chunks. Dust and fire billowed out ahead of them in a blackened plume.

Praetor glared through the smoke and carnage, filtering out the interference from the explosion’s aftermath. He muttered something. The rest of the squad had assumed battle positions, expecting another ambush. The sergeant consulted the scanner of his retinal display. He did this several times before he swore, an old Nocturnean curse.

‘Brother-sergeant?’ asked Vo’kar.

‘Our way back is closed.’

‘Lord?’

Praetor rounded on him, his fury affecting the burning embers in his eyes and setting them ablaze.

‘We cannot proceed, brother! The Traitors have collapsed it. And unless we find another route to the central power chamber, Nu’mean and his squad are dead!’

The respite would not last. The cleansing fire of Brother Kohlogh’s heavy flamer had done its work well. Ashen genestealer bodies littered the corridor ahead, but more were coming, many more.

Nu’mean had his ear to the comm-feed, listening to Praetor’s grim report. The conversation ran in several one-sided bursts.

‘I understand, brother.’

‘Do not attempt it. Cutting through will take too long.’

‘Another route? There is none that will get you here fast enough.’

‘You must. I can get Brother Emek off the hulk. His life is the only one you can save now.’

‘In Vulkan’s name,’ he echoed the last transmission under his breath after he’d cut the feed.