Suddenly the simple ships of the nightsiders had been equipped with faster drives and still deadlier weapons. Swimmer, with a resigned acceptance, had come to believe that his people’s time was up - until, in the form of the humans, he had stumbled on his own miracle from the sky.

Hex was distracted by a shadow crossing the cave mouth.

Hella was growing excited. ‘Pilot, I think I’ve figured it out—’

‘Shut up,’ Hex hissed. The shadow crossed again. Now she was sure: it was a palette-ship, and four, five, six Ghosts, angular rhomboids, rode it menacingly. Hastily she shut down their packs, and made her crew lie flat. Even Swimmer lay still in his puddle of slime.

The palette paused briefly at the cave mouth, but anything within was hidden by the fire. With a careless burst of an energy weapon the Ghosts smashed Swimmer’s hearth, scattering its fuel. Then the palette moved on.

The crew stood up cautiously.

Borno said, ‘So they’re looking for us. We have to get out of here.’

Hella grabbed his arm. ‘Not before you listen to me. I’ve worked it out. This world is—’

‘The home world of the Ghosts,’ Borno said, dismissively. ‘And this is their origin, from a million years back or so, somehow brought forward in time. Isn’t that obvious?’

Not to Hex. Her jaw dropped; she deliberately closed it.

Jul was figuring it out too. ‘Yes, yes. Swimmer speaks a variant of one of their languages. Ghosts are cooperative organisms, just like Swimmer. Even their hides were once independent creatures—’

‘Every Ghost is a whole ecology in a sack,’ Borno murmured, repeating training-ground lore.

Hella said, still excited, ‘We even found a copy of this system thirty light years away! That must be the present-day copy - this one is dredged up from the past . . .’

Jul said, ‘The “primitive” Ghosts must come from this world. The Black Ghost recruited them here.’

‘Maybe that’s why this was done,’ Borno said darkly. ‘The Black Ghost has tapped its own deep past for raw material for the war with humans. When Ghosts told us about their origin they never mentioned this devastating civil war, did they? Funny, that.’

Hella turned to Hex. ‘Pilot? You’ve been very quiet. What are you thinking?’

Hex looked at her, abstracted. ‘About time travel.’ Humans had achieved time travel, of course. Every faster-than-light ship was a time machine, and it was said that in the old days the legendary hero Michael Poole once travelled through time in a wormhole. ‘We’ve sent a few people, a ship or two, through a few centuries. But the Ghosts have brought a star system, a whole system, up through a million years.’

That sobered them.

Jul said, ‘The Integumentary did say that their new extra-dimension technology was opening up vast energy sources for them.’

‘Yes. But I never dreamed it would be capable of something like this.’