Sanguinius walked across the Red Tear’s bridge, taking in the portrait of the planet emerging from the combined rapid scans of the fleet as they developed on the arrays of auspex screens. It was a small, rocky world, not much larger than a planetoid, less than three thousand miles in diameter. Steep mountain chains dominated much of the south, diminishing as they approached the equator. Tens of thousands of years of intensive mining in the once-inhabited northern hemisphere had worn the peaks down. The composite images of the north showed the traces of human civilisation and industry, now twisted almost past the point of recognition. Manu­factoria taller than the mountains they had replaced belched fire and smoke into the world’s eternal night. A spiral pillar, five hundred miles wide, linked the north magnetic pole of Pyrrhan to the bottom of the gate. It emerged from the greatest manufactorum, a jagged monster that rose from the surrounding terrain like two gigantic, clawed hands clasped in prayer. There was no clear division between manufactorum and pillar. They flowed into one another, and the pillar flowed into the gate. The pillar shone with the light of molten matter.

Sanguinius took what he saw with him to the hololith chamber. ‘Matter,’ he said to the images of his brothers. ‘Matter is being created at this juncture. We can observe it happening. The pillar grows from the manufactorum. The gate’s being is forged here.’

‘It cannot be the planet’s own matter,’ the Lion said. ‘It is a speck compared to the gate. It would have been consumed a million times over by now.’

‘There is nothing about what we are seeing that is rational,’ said Guilliman. His jaw was set with frustration. He said rational with something like bereavement. ‘This fortress is already impossible a million times over.’

‘Yet Pyrrhan is somehow necessary to it,’ Sanguinius pointed out. ‘The impossible has attached itself to something real.’

Guilliman’s eyes widened in the hope of reason. ‘An anchor,’ he said. ‘The fortress needs to anchor itself in the materium. Maybe Pyrrhan’s industry, in the new configuration, is a gateway, funnelling in the warp’s substance, making it into stable matter.’

‘That conforms to what we are seeing,’ said Sanguinius. ‘The intensity of the energy suggests an important nexus of some sort. Brothers, I would thrust a sword into that heart and sever the connection.’

Guilliman nodded. ‘Destroy the forge. Shut down the flow of matter. Perhaps that might destabilise the gate.’

‘We are under attack,’ said the Lion. ‘So we must now constitute a threat. The enemy does not want us on Pyrrhan.’

‘We can’t move close enough to the target zone to stage a drop,’ said Guilliman. ‘The defences will take the fleets apart before we could launch even a fraction of the ground forces we’ll need.’