The Heptaligon suffered for its role as battlefield. The Space Wolves were not neglecting the station. Heavy bombardment blasted columns of shattered ice from the surface of Momus that escaped easily from the weak gravity well. Seconda Station had broken free from its tower, and floated away with strange serenity, like a leaf in a stream. Its mooring collapsed slowly towards Momus, spewing burning atmosphere from the ragged end. Space Marine gunships duelled over the moon. There were even, he saw, groups of warriors wearing void jets fighting outside. Cawl was no expert in the field of void war, but he thought the Space Wolves unlikely to make it out of the system. The Warmaster's subsidiary fleets, comprising elements of the many Legions loyal to him, were moving in from the other small worlds to join the battle. Russ' Legion faced a large part of the Sons of Horus. The skill of the VI Legion was widely known, but they were outnumbered at least two to one. Cawl could think of only one good reason why Leman Russ would be behaving so.

Friedisch's pallid, nervous face appeared at Cawl's shoulder.

'This is suicide!' he said.

'They have come to kill the Warmaster,' said Cawl. 'Isn't it obvious? Leman Russ has committed his entire Legion. He's the Emperor's executioner. He's come for the Warmaster's head.'

'Look!' shrieked Friedisch. He pointed with a shaking finger.

Cawl turned to look. The tube-spars surrounding the trunk of the Septa station were coming apart. Some attacks were targeted upon the giant shaft, but many appeared to be incidental to the battle going on around the moonlet. The Heptaligon's void shielding was minimal, graded only to protect the station from cosmic debris. A missile struck the weakened tube he and Friedisch had exited. The resulting explosion turned a fifty-metre section into a glittering haze of particulates. Tethering hawsers snapped like spider's silk The spar bent away from the trunk of the tower, until acceleration and material stress sheared it off and it floated away to add to the growing mass of battle debris. The trunk was as yet firm, but was marked with many holes, and it vibrated with the impact of city-levelling weaponry. It would not stay intact forever.

'Blood of the machine,' said Friedisch. 'That could have been us.'

'They're coming,' said Cawl.

Shoals of boarding torpedoes rocketed out from a frigate that dipped low towards the Septa shaft. The frigate was under attack and coming apart even as it disgorged its armies. Dozens of the torpedoes were obliterated by raging point defence fire, but far more made it through. A different sort of impact shook the tower. Shortly after, new noises reached them from down the endless corridor, a throaty howling and the awful flat banging of Space Marines small-arms fire.