Soon the clutter of threads cleared away, and the big central bastion was revealed. It was a sphere, black as night, kilometres across. In the jungle-like tangle of Ghost architecture it didn’t fit; it was alien within the alien.

‘That wall is a perfect absorber of radiation,’ Jul called. ‘A black body.’

‘You see what this is,’ Borno brayed. ‘The Black Ghost built its central bastion in its own image. What arrogance!’

Hella murmured, ‘Haven’t human rulers always done this?’

Hex said, ‘I’m hoping we can use its arrogance against it.’ She inched forward cautiously. Still they weren’t challenged. The hull of the bastion was a smoothly curving blankness before her, reflecting not a photon of starlight. She sensed the Black Ghost in there somewhere, watching, drawing out the moment as she was. ‘Come on, you bastard,’ she muttered. ‘You know I’m out here. Let’s see what you got.’

The black wall quivered. Then it split along a seam, revealing a pale silvery glow. When the wound stopped dilating it was a vertical slit hundreds of metres long, more than wide enough for the palette to pass.

‘I can’t see inside,’ Jul said.

‘Our suit sensors don’t work,’ Hella said, sounding alarmed.

‘But the invitation’s clear,’ Hex said tightly. She brushed her hands forward.

The walls of the bastion slid past her; the fortress’s hull looked no more than paper-thin. Twenty metres inside the hull she brought the palette to a stop. Her visor showed her nothing but empty space, a sphere kilometres wide filled with a cold silver-grey glow.

Then the ur-Ghost hide around her began to crumple and blister, and a harsher light broke through, shining directly on her. She threw up her hands to protect her vision. She heard the others cry out. The hide, scorched, crumbled and fell away.

Cautiously she lowered her arms. Now she could see what the sensors hadn’t been allowed to show her. This space wasn’t empty at all. It was filled with Silver Ghosts, spheres like droplets of molten metal, and ur-Ghosts of every shape and size, faceted and spiny, ranked around her in a hexagonal array that filled space as far as she could see. They were motionless, positioned with utter accuracy, objects of geometry rather than life. And, scattered through the ranks of silent Ghosts, lanterns pulsed, blue-white: models of the pulsar that was destroying the world, they were marks of adherence to the Ghosts’ Destroyer god.

This was nothing like the way humans had seen Ghosts behave before, over centuries of contact and warfare. The command of the Black Ghost, here at the heart of its empire, was total.

Hex’s palette-ship hung like a bit of flotsam before this symmetrical horde. With their skin covers burned away, her crew sat cross-legged in their little hollows, cowering. ‘Everybody OK?’

‘What do you think?’ Jul said.