The blazing crozius swept down in hissing arcs, smashing helmets and crushing bone. There was nowhere to run in the narrow space; nowhere to manoeuvre or try to sneak around Nemiel's flanks. The rebels were forced to stand and face his wrath directly, and he slew them without mercy. When their courage finally broke and they turned and ran down the remaining length of the rampart, Nemiel realised he was thirty metres past the second-storey ramp, and his armour was caked in blood up to mid-thigh. He'd been treading on burnt and broken corpses for a full ten minutes.

Down on the tramway another APC exploded in a shower of molten steel. Brother Titus and the rest of Kohl's squad were almost to the berm, and the remaining rebel troops were in full retreat, withdrawing on foot as quickly as they could down the tramway in the direction of the captured star port. Behind Nemiel, Cortus, Ephrial and Marthes were trading fire with the rebels on the second storey. The Redemptor slapped a fresh magazine into his bolt pistol and went to join them.

The rebels fought doggedly, forcing the Astartes to fight for every metre they climbed, but the Dark Angels were relentless. Nemiel took the lead once more, firing away with his bolt pistol until he could draw close enough to wield his deadly crozius. He was wounded half a dozen times. Las-bolts burned through weakened spots in his armour and seared the flesh beneath. Once a rebel soldier charged him with a bayonet-tipped lasgun and jammed the blade into the joint of his left hip. The point dug deep into his flesh and snapped off when Nemiel smashed the man to the ground with a backhanded sweep of the crozius, but the injury scarcely slowed him by that point. Victory was close at hand.

They threw the last of their grenades at the top of the third ramp, and they rushed forward to meet the rebels' last stand. Ephrial fell during the charge, shot through the right knee. He landed on the permacrete, his crippled leg extended beside him, and continued to blaze away at the enemy with his bolter. At the top of the pyramid the Astartes were able to spread out and attack the enemy at once, and a wild melee raged for almost three full minutes before the last of the rebels fell beneath Nemiel's crozius. He searched among the bodies for the commander of the detachment, but there were no officers to be found.

'North bastion secure,' Nemiel reported over the vox. 'One casualty.'

'South bastion secure,' Brother-Sergeant Kohl answered a minute later. 'No casualties to report.'

'Gateway secure,' Brother Titus reported. 'Brother-Redemptor Nemiel, I am detecting movement inside the forge complex; approximately six contacts, heading this way.'

'Very well,' Nemiel replied. 'I'm coming down. Brother-Sergeant Kohl, leave one member of your section behind as a lookout, then link up with me in the gateway.'

Nemiel left Brother Ephrial behind to stand watch from the northern bastion and headed down to ground level. Off to the north-west, he could hear the rumble of petrochem engines and the squeal of tank treads. New signals over the company command net indicated that the Tanagran Dragoons had broken through and were almost to the tramway.

Kohl and his warriors reached the gateway at the same time as Nemiel. Brother Titus stood squarely in the breach, his smoking assault cannon trained down a wide avenue that ran northeast into the vast complex.

'Where are the contacts now?' Nemiel asked the Dreadnought.

'Two hundred metres northeast,' Titus answered. 'I'm getting strange returns on my surveyors. Whatever they are, they are making good use of cover and avoiding direct line of sight.' He paused. 'I don't think they are rebel troops.'

'It could be Tech-Guard,' Askelon said. 'There has to be a garrison of some kind here to defend the forge.'

'Let's hope so,' Nemiel replied. 'Although it looks like the enemy managed to penetrate at least into the outer districts before we arrived. We need to investigate the returns, no matter what.' He turned to the Dreadnought. 'Hold the gate, Brother Titus. This shouldn't take long.'

Nemiel led the group through the gateway and into the precincts of the Mechanicum. The roadway beneath his feet wasn't permacrete, but a kind of smooth, grey metal cladding. It rang softly with each step, and continued northeast in a laser-perfect line towards the distant slopes of the great volcano. Tall, dark structures rose to either side of the roadway. Warehouses, Nemiel reckoned, or manufactories idled sometime during the rebel attack.

The Redemptor moved forward, peering intently into the shadows surrounding the silent buildings. He knew basically where the six individuals ought to be, but try as he might, he could not spot them. 'They must be around the corner of one of these structures,' he said quietly. 'If so, they likely don't know we're here.'

Techmarine Askelon shook his head. 'I wouldn't count on that,' he replied. 'If they're Tech-Guard, they could have surveyors that rival those of Brother Titus.'

Nemiel didn't like the sound of anything that could see farther and keener than he could. 'Stay sharp,' he told his warriors, and pressed ahead. After just fifteen metres, Brother Titus called over the vox.

'The contacts are moving,' Titus reported. 'They're thirty metres north-by-northeast and heading your way.'

The Astartes orientated on the bearing given by the Dreadnought, their weapons held low but ready. Ironically, it was Brother Cortus, the one-eyed Astartes, who spotted them first. 'There!' he said, indicating a narrow alley off to the left with a nod of his head.

Six figures were spilling from the alley and fanning out in a semi-circular formation, heading straight for the Astartes. As they emerged from the shadows between the buildings, Nemiel could see that they were massive individuals, each one easily as large as an Astartes, and just as powerfully built. Articulated armour plates covered their hyper-muscled bodies, and even from this distance Nemiel could clearly see that their limbs and heads were heavily augmented with bionic and chemical implants. Their arms were fully weaponised, with an assortment of fearsome-looking energy and projectile weapons and lethal close combat attachments. He could hear them speaking to one another in blurts of binaric code as they advanced. Their augmetic eyes glowed a pale green from within burnished metal frames.

Nemiel turned to Askelon. 'What are they signalling to one another about?' he asked.

The Techmarine shook his head. 'I can't tell, sir. It's all highly encrypted. But their weapons systems and combat surveyors are fully active.'

Nemiel turned back to the oncoming figures. 'Do you recognise them?'

'Oh, yes,' Askelon said. 'They're skitarii; more specifically, a unit of Praetorians. They're the Mechanicum's elite guard.'

The Praetorians continued to advance, snapping and squealing to one another in sinister-sounding code. Nemiel took a step forward, making a point to lower his weapons.

'Ave, Praetorians,' he began. 'I'm Brother-Redemptor Nemiel, of the Emperor's First Legion. We've come to help defend the forge—'

The rest of Nemiel's greeting was cut short as the Praetorians raised their weapon arms and opened fire.