The flare of the blasts faded. Geysers of molten metal extended into the void. Burning gas dissipated. A crater as wide as the fleet appeared. It glowed from the heat of its creation.

‘Our auspex readings put the depth of the breach at approximately four thousand miles,’ Guilliman said.

‘It might as well be nothing at all,’ the Lion muttered, disgusted. The crater was a meaningless blemish on the barrier. The wall could be millions of miles thick. There was no return fire. The fleets did not even register as a threat for the things inside the fortifications.

‘This is futile,’ Sanguinius said. ‘We must find another way through.’

‘If there is one,’ said Guilliman.

‘A fortress is a barrier on a path,’ the Angel insisted. ‘Its existence means we must cross it. This is the road we must take.’

‘I will not smash my fleet against this wall to no purpose,’ Guilliman said.

‘We will cross it,’ Sanguinius told him. ‘We do not end here. I must face Horus.’ Sanguinius spoke with the same certainty the Lion heard in Curze’s voice. Both of them lived only partially in the present. The other part of them existed in the inexorable reality of their future deaths.

‘By your logic,’ the Lion said, ‘a wall must have a gate.’

‘Yes. This is not a blank wall. This is a fortress. We see its features. We must find the others. Our long-range scanning shows a different heat signature to port and in the direction of the wall’s base.’

‘A base with what foundation?’ Guilliman asked.

‘Perhaps none. But the shape has meaning. The turrets declare that we are looking at the peak of the fortifications. Their existence implies the presence of a base, foundation or not.’

‘Agreed,’ said the Lion.

‘We are relaying the coordinates of the heat bloom,’ Sanguinius said.

A few minutes later, the fleets began to move, descending the infinite heights of the wall. The search target was as distant from the Invincible Reason as Mars was from Terra. The ship shuddered as if it were passing through an atmosphere, straining to hold its position against the gravitational pull.

Stenius looked back up at the Lion as the ship passed the unending expanse of the wall, its apertures flickering with infernal red, a million eyes staring out, mocking and hungry. ‘Lord,’ he said, ‘what is this thing?’

‘It’s the future,’ the Lion answered. The longer he gazed at the fortress, the more the shock of its size wore off, and the more the implications of its being sank in. ‘This is what the galaxy will become if we do not win this war.’ Did you foresee this, Horus? he wondered. Greater powers are using you. You have opened the door to this horror. I hope we have the strength to close it.

‘Can we destroy this?’ said Stenius.