And then the bridle was inside Tony's head, telling him that she was so happy to be back with him, saying that she hoped that she had done the right thing.

'Yes. Yes, you did.'

'This place is amazing! And the sky! I was able to map it while I was held prisoner. The dark-matter disc at the galactic core? There are strings of organised structures in there. They seem to form a loose ring around the supermassive black hole, with a diameter of about thirty light years. And listen, listen! This is the thing. There are gamma-ray bursts associated with them, and fluxes of tau neutrinos too. I think they may be wormholes. Very strange ones. Very big ones. It's really interesting!'

'What about the planet's sky what's happening up there?'

'Oh, the battle. Yes. That's very interesting too,' the bridle said, and threw a window at him.

The ships of Adam Nevers's expedition hung in formation behind a picket of drones. Several were damaged; the S-class scow, Nevers's command and control ship, had taken a big hit, shearing off part of its hull. Tony briefly wondered if Nevers was still alive, realised that he didn't much care. The surviving ships of the Red Brigade were scattered beyond. A mad ship, its funnel hold shattered, tumbled in a decaying orbit. Sparks flared as drones probed Nevers's defensive perimeter. Much further out, one of the Red Brigade ships was fleeing towards the mirror, no doubt hoping to evade the three police interceptors as they decelerated towards the planet.

Tony pushed the window aside, said to Unlikely Worlds, 'You manipulated Ada Morange. You manipulated Lisa and me so that we would make a pretty story. And now I suppose you want me to tell you about everything that happened while you were hiding in some icy hole. All right. Here's the deal. You'll get my story only if you tell me everything you know about this place. And you go first.'

'Oh, but I already know what happened,' Unlikely Worlds said. 'The rise of this city, the transfiguration of Lisa Dawes, your conversation with the avatars . . . I know everything.'

'The balloon,' Tony said.

'Yes, I saw that you noticed it. I saw everything. So I'm afraid that you don't have anything to trade. I hitched a ride on your ship because after all we've been through together it would be remiss of me not to say goodbye. But now your story is done, so I guess it's so long and thanks for all the fun.'

Tony felt a quick hot spurt of anger, realising how he and Lisa had been used. He had set out to capture Ada Morange and take her back to Skadi so that she could answer for what she had done, and that had been taken from him when Adam Nevers had destroyed Mina Saba's frigate. Lisa had died. Dave Clegg had been killed. Hundreds were dying even now in the orbital battle. He might yet die trying to escape. All because a bunch of alien shrimp in a walking talking tin can wanted a neat end to a story got up from the lives of others . . .

He pulled the ray gun from his belt and aimed it at the !Cha, saying, 'We are not done yet. If you don't tell me what I need to know, I'll boil you in your fucking tank.'

'With that little toy?' Unlikely Worlds said. 'I don't think so.'

Tony jerked up the ray gun and fired. The chamber flared with white light; a patch of the domed ceiling exploded; sand rained down as he re-centred the gun on Unlikely Worlds.

'Oh really,' the !Cha said. 'I can easily absorb a small amount of energy like that, and use it to displace myself elsewhere.'

'Could you manage the same trick with an X-ray laser?' Tony said, and felt the !Cha's attention focus on him.

'Adam Nevers stripped out or deactivated your ship's assets,' Unlikely Worlds said.

'The stuff bolted to the hull, perhaps,' Tony said. 'But the laser is inside the ship, built into the lifesystem machinery. It will punch a tiny hole in the hull if it is fired, nothing I can't easily repair. But what will it do to your tank?'

He was lying, as he'd lied to Dave Clegg about his ship's weaponry, but after two years of negotiating with traders, freebooters, brokers and customs officers he believed that he could bluff with the best of them. And hoped that there were limits to the !Cha's insight into human psychology, because the threat of the non-existent X-ray laser was all he had.

'That's interesting,' Unlikely Worlds said. 'I suppose I should ask your ship if it's true.'

'Go ahead,' Tony said, even though he wasn't certain that the bridle would have the sense to back him up. 'But I don't want much from you. Just the answers to a few questions that the Jackaroo pretended to ignore.'

He sweated out a long silence. At last Unlikely Worlds said, 'You guessed that this world is a library. And the Jackaroo told you that they had nothing to do with its construction. I suppose it will do no harm to tell you that much is true.'

'Then you know what this place is. What it is for, what it can do.'

'I have heard of it. It certainly lives up to its reputation.'

'And when Lisa died, she became part of it.'

'I believe so.'

'Can I talk to her? Can you?'

'You are anxious to discover what has been left here by so many, over so much time. I understand. Unfortunately, I know no more about its operation or what it contains than you do. However, I could tell you a little about the Jackaroo. If you're interested, that is.'

Tony stowed the ray gun in his belt. 'You've followed my story, such as it is. I'd love to hear one of yours.'

'In every series of events, there must be a first,' Unlikely Worlds said. 'And so it fell to a certain species to evolve the first technological civilisation in the galaxy. Its people developed space travel and explored the stars. It took a long time, and at the end of it they realised that they were alone. Unique. And so, a little while later, they went elsewhere. Whether they ripened into something beyond our understanding, shifted to a more congenial plane of existence, or simply died out, I do not know. But a little later the Jackaroo are as vague about time as they are about everything else the legacy of those pioneers was taken up by what may have been a parasitic species, or a species of commensals like your dogs.'

'Dogs? Is that why the Jackaroo say they like to serve?'

'They are not exactly dogs. I am using a homely analogy to help you understand ancient and almost incomprehensible events and actors. Whatever they were,' Unlikely Worlds said, 'exposure to certain legacies of the pioneer species caused the progenitors of the Jackaroo to develop a limited form of intelligence. Part of your intelligence, your self-awareness, is chunked from routines that have evolved to cope with a variety of situations common to the habitat of your distant ancestors, but those routines can be overridden by a focal point that is not only attracted to novel situations, but actively creates them. The Jackaroo lack that spark of creativity and curiosity. They are creatures of habit and routine. Their intelligence is very finely chunked and partitioned, so that it can cope with a huge number of situations, but that is all there is to it. They never think new thoughts; they do not create new situations.

'I confess that we are something like them. We seek out new stories because our females crave them, but we cannot create our own. Perhaps that is why the Jackaroo tolerate us. They know that we cannot be anything other than what we already are. In any case, they went out into the galaxy using the wormholes built by the pioneers, they found intelligent species which possessed the spark and curse of curiosity, and they helped them as best they could. And because they lack the ability to change, that is what they have been doing ever since.'

'It is a nice story,' Tony said. 'But how much of it is true?'

'It is a story collected from a client race by someone who lived long before I did,' Unlikely Worlds said. 'I heard it from someone whose distant ancestor told it to woo his mate. Whether he discovered a true story or merely believed he did, or if he stitched it from half-truths and elisions, I cannot say. But our females can taste truth. And his was one of the most exacting mates in our history she had killed a hundred suitors before he won her affection. So even if it is not true in every part, it has the ripeness of actuality. If you want to know more than that, you must look around you.'

'You mean that some of the Elder Cultures may have discovered the truth about the Jackaroo, and put it in the library?'

'Yes, why not?'

Tony thought about that for a moment. 'Was Nevers right? Will it destroy us?'

'The Jackaroo bring gifts, but what their clients do with those gifts is always up to them,' Unlikely Worlds said. 'And if you are going to do anything here, you should do it quickly. Your ship came to find you because it was safe to do so. It won't stay safe for very much longer.'

Tony said to the bridle, 'Can we get past the trouble up there?'

'I have a plan,' she said. 'We can gain velocity with a gravity-assist manoeuvre around this planet's star, and head out to the mirror while the police are finishing off the Red Brigade.'

Tony took thirty seconds to review the schematics that she threw to him. 'Let's do it. Send a sled. We have a passenger.'

He put on his helmet and hefted Lisa's body her faceplate was frosted over now and carried it down the passageway. His suit registered an alarming jump in radiation levels, but it did not matter. Because there was the sled, waiting at the entrance, and there was Abalunam's Pride, floating just above the expanse of rippled red sand. He had never before seen anything so lovely.

High above, ragged contrails radiated out from a central point as a drone, trying to escape a pursuer by dipping into the atmosphere, was blown apart.

'The main part of the battle is presently above the dark side of the planet. We have fifteen minutes before it rises above the horizon,' the bridle said. And then: 'Wait. Wait. Something happened. Something just came through.'

She sounded distracted. Dazed.

'If Nevers or the Red Brigade are trying to hack you, shut down all comms now,' Tony said.

'It didn't come through the comms. It just appeared in my storage space.'

'What is it?'

'It appears to be information of some kind. So much information!'

'What kind of information? Can you read it?'

'The language and code are unknown, but there are mathematical expressions that may aid translation . . . It just appeared. All of it, all at once. Isn't that amazing?'

Tony looked at Lisa Dawes's frosted faceplate, looked at Unlikely Worlds. 'It was her,' he said. 'Wasn't it? It was her. She followed her eidolon into the library and hacked it and passed on what she found.'

'I doubt if it is all of it,' the !Cha said. 'A sample, perhaps. A selection.'

Tony laughed. 'Ancient knowledge. Secrets of the gods.'

'More stories, certainly.'

Tony set Lisa's body on the sled, then stiffly knelt and scooped up handfuls of sand and tipped them into a pocket on the thigh of his pressure suit.

'We are going back to Skadi,' he told the bridle. 'And we will take revenge on Adam Nevers and the Red Brigade by researching the hell out of Lisa Dawes's gift. How to read what she gave us, how to use it. This sand, too. And I'm going to tell everyone about it. If I do nothing else, I'm going to make sure that no one can keep this place a secret.'

'I thought you were in trouble with your family,' the bridle said.

'I'll find a way to make amends.'

Lisa's gift and the sample of smart sand would help. And he would have to try to find a way of making amends with Danilo, too.

He asked Unlikely Worlds if he needed a lift. 'Or are you hoping that Adam Nevers will come to collect you?'

'Oh, I rather think his story is over, don't you?' the !Cha said. 'You go on ahead. I'll hitch a ride with the police, when they come.'

'Time to go,' the bridle said.

'Time to go home,' Tony said.

67. Unlikely Worlds.

He stood in a skirl of blown sand, watching the ship punch straight up into the sky. A touching sight, like a hatchling wriggling through the skin of the sea onto land.

Around him, quietly and without any fuss, the city was crumbling into myriad minuscule grains and blowing away on the lightly radioactive wind. For a moment he glimpsed a woman a little way off, a dog at her side, and then she too was gone. Lisa Dawes. She was stubborn and clever by human measure, but sooner or later, like all who had gone before, she would dissolve into the library's gestalt and minutely enlarge its store of knowledge and experience.

Now the ragged remnant of the battle between the Commons police and the Red Brigade was dawning in the east. Several dead ships hung in expanding clouds of wreckage. The lifesystem of Adam Nevers's ship was shredded, and its bias drive was misfiring, shedding turbulent wavelets of hot mesons as it tried and failed to grapple with the local gravitational gradiant. Perhaps Nevers was dead. Perhaps he would survive and try to lay claim to the library planet, and Tony Okoye would lead an insurrection to take it back. Or perhaps Tony would be reconciled with his family and his lover, and live a quiet fulfilling life extracting and deciphering the ancient knowledge in Lisa Dawes's gift, finding cures for meme plagues and much else . . . But that was another story.

Yes, it was time to go, Unlikely Worlds thought. He had been a long time wandering Earth, the Jackaroo gift worlds and the worlds of the network. He had collected many stories, and now the longest and most intricate had reached an ending. He wasn't interested in what happened after that. One of his rivals could take it up if they wanted to, but he had the best of it, and he had given something in return. It was a human concept, this reciprocity, but he'd been amongst humans a long time, imitating them to make them feel at ease, to allow them to think that they understood him.

Humans were afraid of the Jackaroo, but believed that the !Cha, with their clumsy aquarium tanks, their candour about their interest in the small change of human lives and their penchant for certain chemicals in culturally acceptable beverages, were comical and harmless. Unlikely Worlds mostly told the truth about why he collected stories because why not? But much of the rest . . . He didn't think of it as lying. It was camouflage. A necessary deceit. An illusion of amity and goodwill that helped him to harvest his prize.

So let humans think he was a shoal of funny little shrimp in a tank. Let them believe the pretty story he'd given them, with its flattering insinuation that they were heirs of an ancient race from the dawn of time. The truth was, no one had ever discovered the origin of the Jackaroo, or what they really were the best most likely guess was that they were a kind of virus spawned by glitched algorithms in some long-lost library or repository like this one.

Oh, and it would be kind to let humans think that they were the focus of the Jackaroo's attention, when really, as far as the Jackaroo were concerned, they were no more than the progenitors of a better, more promising form of intelligence. The Ghajar had discovered that, too late as usual, and had fought and lost a war over it. Organic intelligence rarely made the crucial leap to true intelligence, but the so-called AIs that human beings had made to mediate between themselves and the Ghajar ships were already taking the first steps towards it.

While waiting in the ice on the far side of this little world, Unlikely Worlds had enjoyed a very useful conversation with the bridle of Abalunam's Pride. The Ghajar eidolon had changed her in several interesting ways, and she hadn't finished changing yet. And then there were the Ghajar ships in their sargassos especially the so-called mad ships, which had been trembling on the brink of a similar change when they had been quarantined. Perhaps that precocious little AI would be the catalyst for their transfiguration.

It was possible that something in the trove of knowledge Lisa Dawes had passed to Tony Okoye would set humans on that path. It had happened before. It would no doubt happen again. But mostly those who believed that they were the clients of the Jackaroo flowered all too briefly before failing. Ghajar, Ghostkeepers, Boxbuilders, Spirebuilders, Constant Gardeners and several hundred others: all were gone. Some had failed in interesting ways. Some had burned quickly and brightly. Some had lingered long before finally fading. The descendants of a few lived on, unburdened by complex consciousness. Hive rats on First Foot, wind skimmers on Yanos . . . So while it was possible that humans might bootstrap themselves into transcendence, it was more likely that it would be the descendants of the union between bridles and ships who would discover how to access the dark-matter gates that orbited the supermassive black hole, and go through to wherever they led. Into other galaxies. Into polders where unimaginable intelligences dwelled. Into the calm depths of the far future, beyond the brief epoch of light and matter. Into the deep past, where they could flake off new universes from the infinite possibilities that nested in primordial creation. Into everywhere. Their evolution would take a long time a thousand years, ten thousand to reach fruition, but it had begun. Now there was a story . . .

But Unlikely Worlds was done with all that. He could have hitched a ride with the winners of the petty squabble climaxing overhead, but he didn't need to. He went up, heading straight for the wormhole, flying faster and faster and faster.

Time to go home.

Time to woo and win and wed.

That much, at least, he'd told true.

Acknowledgements.

My thanks to my agent and first reader Simon Kavanagh, my editor Marcus Gipps, Nick Austin for his scrupulous copy-editing, Sophie Calder for putting out flags, and all at Gollancz and Orion Publishing who helped to turn this into a book and aim it at the world. Life support was, as always, unstintingly provided by Georgina Hawtrey-Woore. Thanks also to Stephen Baxter, Pat Cadigan, John and Judith Clute, Barry Forshaw, Chris Fowler, Jon Courtenay Grimwood, Maura McHugh, Alastair Reynolds, and Russell Schechter.

Willie's kan is based on Alasdair Gray's short story 'Humanity', collected in Lean Tales by James Kelman, Agnes Owens and Alasdair Gray (Jonathan Cape, 1985).

Also by Paul McAuley from Gollancz.

400 Billion Stars.

Cowboy Angels.

Eternal Light.

Fairyland.

Pasquale's Angel.

Red Dust.

The Quiet War.

Gardens of the Sun.

In the Mouth of the Whale.

Evening's Empires.