'There'll be time for that later, ma'am.'

The agent was a trim young African-American woman with an accent from somewhere in the Deep South. She'd taken off her jacket to reveal her shoulder harness and the automatic pistol holstered under her left arm. According to the photo ID she wore on a lanyard her name was Aimee Cutler.

Lisa said, 'Exactly what have I been charged with, again?'

'That is what we are here to determine, ma'am. The coffee's not so bad. Or if you like I can fetch a soda.'

After Agent Cutler delivered a cardboard beaker of thin burned coffee, Lisa was left alone again. A tactic to weaken her, she supposed. To let her worry about the deep shit she was supposedly in.

More than an hour passed before the agent returned, toting a tablet and a document case, followed by Adam Nevers. Lisa did her best to hide her relief that this time he wasn't accompanied by the Jackaroo avatar. She didn't know if she could stand being cooped up with the fucking thing in this cramped cell.

'Agent Aimee Cutler and Chief Investigator Adam Nevers questioning Lisa Dawes,' Nevers said, after he had settled on the other side of the table. He gave the time and date, told Lisa that the interview was being recorded and that she should remember she was under caution.

Lisa looked him in the eye and said, 'I'd like to talk to my lawyer.'

Nevers smoothed the point of his neat little beard between finger and thumb, a gesture that reminded Lisa of a second-rate stage magician she'd once seen. 'We can do that,' he said, 'but it would put things on a formal footing. Are you sure you want that?'

He was dressed in a grey silk suit today, a burgundy tie with a yellow stripe on the bias, his usual crisp white shirt.

'I'm handcuffed to this table,' Lisa said. 'How much more formal can it get?'

Nevers glanced at Agent Cutler; the woman stood up and unlocked the handcuffs. Lisa massaged her wrists while Nevers told her that she wasn't under arrest because at the moment he didn't see the need.

'So am I free to leave?'

'You're under caution. If you refuse to cooperate or demand legal representation, I'll have to charge you. Under the terms of the Technology Security Act we can hold you for forty-eight hours without access to legal support, and you'll be asked the same questions I'm going to ask you anyway. So I hope you see that it's to your advantage to keep things informal.'

'Charge me with what?'

Nevers ignored that. 'You are here to help us with our inquiries. As is your friend, Ms Mendoza-Trujillo. I've just had a very interesting conversation with her. I hope you'll be equally cooperative.'

He paused, letting Lisa think about that. A classic prisoner's dilemma tactic. Threaten two suspects separately, offer each of them the chance to betray the other. But Lisa was certain that Bria would have told Nevers everything he wanted to know. She was an upstanding citizen who believed that she didn't have anything to fear from the police, and she would be concerned about her business, her employees, her livelihood. Yes, absolutely, she would have talked, and Lisa didn't blame her one little bit.

'Let's start with the stone,' Nevers said. Agent Cutler unzipped her document case and took out a plastic bag and laid it on the table. It contained the tessera.

Lisa was certain it had been truffled out by the avatar which had accompanied Nevers and his agents when they had pitched up at her place for the second time. So much for her hiding place.

Nevers said, 'For the record, I am showing Ms Dawes evidence article number BK89 slash zero three eight. Do you recognise it, Ms Dawes?'

'It looks like a tessera,' Lisa said.

'Is it the tessera formerly owned by your husband, William H. Coleman?'

'I'd have to take a look at what it contains before I can answer that.'

'We dug it up from its hiding place inside your barn,' Nevers said. 'Would you like to reconsider your answer?'

'It isn't illegal to possess tesserae,' Lisa said. 'I deal with them all the time.'

'And where did you get this particular tessera, Ms Dawes?'

'I think you know where.'

'I'll remind you again that you're under caution. Refusal to answer my questions could have serious consequences.'

'If you're going to arrest me then arrest me.'

'If I arrest you, you'll stay in jail overnight, come back here tomorrow. And you'll still have to answer the question. And if, as you believe, we already know the answer, what will you have proved?'

Lisa decided to call the man's bluff, partly out of stubborn pride, partly because she did not like him. 'I can't tell you because I signed a contract with my client.'

'So you are claiming, what? Client confidentiality?'

'Exactly.'

'Show Ms Dawes evidence article number BK89 slash zero two six,' Nevers told Agent Cutler.

The woman extracted a sheet of paper in a plastic sleeve from her document case, laid it on the table in front of Lisa.

'That was found on your kitchen table,' Nevers said. 'Could you tell me what it is?'

Lisa saw that he was definitely enjoying this. She wondered, with a flush of shame, if they had also checked her waste bin, found the empty vodka bottle.

'You know damn well what it is.'

'For the record. Please.'

'It's a contract.'

'Is that your signature?'

'Yes.'

'And the contract is between you and a party named Brittany Odenkirk,' Nevers said. It was not a question.

Lisa nodded.

'For the record, Ms Dawes confirmed that this is a contract between herself and Brittany Odenkirk,' Nevers said. 'It concerns the tessera, doesn't it?'

'If you know about it, why ask me?'

'We're trying to establish what you know, and your level of cooperation. Which is, to be frank, disappointing,' Nevers said, fixing Lisa with his gimlet stare. 'Am I correct in thinking that Ms Odenkirk was your husband's girlfriend?'

'We were only technically married.'

'Your husband gave her the tessera. And she gave it to you.'

'She lent it to me,' Lisa said, with a pang of guilt.

'Did your husband give her anything else?'

'You'd have to ask her.'

'If you could answer the question,' Nevers said.

'I did. I don't know.'

'You work as a freelance analyst.'

'On and off. Mostly off, these days.'

'Amongst other things, you extract and analyse algorithms stored inside tesserae.'

'Stored inside some of them.'

'I believe that you analysed this particular tessera yesterday. Would you like to tell me what you found?'

'It contains Ghajar narrative code,' Lisa said. Nevers would have got most of the story from Bria, and his techs would have ripped out the files in the borrowed laptop besides. 'No one knows what it does, what information it contains, but it's basically harmless.'

Nevers was giving her that look again. She wondered if the Jackaroo avatar was watching on CCTV, had a wild thought that Nevers could be a puppet, fed orders by some kind of implant. There were stories, urban legends, that the Jackaroo had cultivated human avatars a secret race bred from people kidnapped thousands of years ago, raised in Jackaroo ships or on some alien planet, and sent back to Earth to observe and report to their masters, or to interfere directly with history. If anyone was a Jackaroo spy, it would be Adam Nevers, with his semi-detached manner and barely hidden contempt for other people.

He said, 'You examined the tessera with the help of Ms Mendoza-Trujillo, didn't you?'

'She had the equipment I needed to extract the code safely and securely,' Lisa said. 'I don't, any more, because you took my stuff. You still have it, as a matter of fact.'

Nevers ignored that. 'And you were also studying it at your home. Wasn't that rather dangerous, seeing as you didn't have the right equipment?'

'I didn't need a trap because I was working with a mirrored image of the code, in a virtual sandbox. Bria helped me extract and mirror it. It was entirely routine.'

'Entirely routine, except for the fire in the code farm owned by your friend Bria Mendoza-Trujillo.'

'A fire? What kind of fire?'

'The serious kind,' Nevers said. He was watching her with clinical interest, like a lab technician noting the reaction of a rat after it had been given an electric jolt.

'Is Bria all right? Her people?'

'No one was hurt, as far as we know. The fire marshals are working up the scene right now. According to them, the place is a total write-off.'

'When did it happen?'

'It was called in at a little past midnight. Are you saying that you didn't know about it until now?'

'If you're trying to imply that the code did this, I don't buy it,' Lisa said. 'We used standard quarantine protocols when we worked on that tessera. And as I've already said, there was nothing about the code that suggested it was in any way malign.'

She was remembering the fire in the code farm that had discovered the Ghajar navigational data some years back work that had led to the opening of the New Frontier. There had been talk back then that the Jackaroo had been responsible, either as punishment for the code monkeys' presumption, or as a preventative measure, destroying as yet unanalysed algorithms and datasets that contained deeper secrets. The location of Elder Culture home worlds, say, or images of the actual Jackaroo, the unseen creatures that controlled the avatars. Lisa had always discounted that kind of truther conspiracy bullshit until now.

Agent Cutler woke her tablet, showed Lisa the image it displayed. It took her a moment to figure out what she was looking at. Everything was charred and ruined, wet ashes and blistered wood and the melted remains of a desk chair.

'Do you recognise it?' Nevers said.

'It looks like a workstation,' Lisa said, with freezing caution.

'Is it the workstation where you and Ms Mendoza-Trujillo extracted the code from the tessera?'

'I can't say for sure.'

Agent Cutler tapped the tablet; it yielded a new image. A sooty surface shingled with blistered rectangles.

'Ms Mendoza-Trujillo says that the workstation was decorated with postcards,' Agent Cutler said. 'Postcards like these.'

'Then I suppose this could be where we were working,' Lisa said reluctantly.

'Ms Mendoza-Trujillo says that it was,' Nevers said. 'And the fire marshals believe that it was the seat of the fire. Where it started. So tell me, Ms Dawes, do you still believe that this so-called narrative code is "basically harmless"?'

18. The Slint.

Aunty Jael's plan was elegantly simple: break into the transceiver, force it to send a fault signal, and wait for the traitor to come to check it out. She told Tony that they should wait for three or four days before baiting the trap because the traitor might become suspicious if the transceiver failed immediately after the discovery of the Ghajar eidolon, but he told her that he wanted it done straight away. If they waited too long, Opeyemi might tell the family council about the traitor, and that would be the end of everything. And it was also a matter of pride. Opeyemi's discovery of the clandestine messages was a humiliating black mark that could be countered only by an audacious act of cunning and bravery.

That was why, after the transceiver had been hacked, Tony chose to wait inside the transformer shed with Junot Johnson and one of Aunty Jael's hands. He wanted to arrest the traitor himself, saw himself standing in front of the council, explaining how security had been compromised, how he had intervened, and why it meant that the work was vitally important. He would win more time for the wizards; they would find something astonishing; he would get back his ship. It was all good.

He sat on the floor with Junot Johnson in the humming, ozone-scented darkness, sharing a small window that displayed feeds from drones stationed outside the shed, trying not to think about the eidolon in his head. Aunty Jael had scanned his brain activity and confirmed its presence, told him that it had imprinted itself within a small tangle of neurons in his temporal lobe and was at present mostly inactive.

'My work with the wizards suggests that it is stimulated only by the narrative code,' she had said. 'If it is no more than a simple translation device, it is nothing to worry about.'

Which did not mean that he was not worried. Far from it. Like every freebooter, he had heard all kinds of cautionary tales about wild algorithms infecting the unwary and driving them crazy, and now something very like those storied horrors was curled up like a tapeworm in his brain. He wanted to believe Aunty Jael's reassuring diagnosis, could not help wondering how he would know if he began to think thoughts that were not his own . . .

Hour bled into uneventful hour. Tony fell into a doze, woke from a muddled dream about chasing Cho Wing-James through a host of inhuman statues carved from stromatolites. Junot said quietly, 'Someone is coming.'

'Give me the window.'

Tony recognised the stolid silhouette at once: Eli Tanjung. He and Junot stood, pulling up the snorkel hoods of their camo cloaks. They were armed with fat-barrelled guns that fired sticky foam pellets, ready to immobilise the traitor as soon as she touched the transceiver. Aunty Jael's hand, crouching up in a corner of the ceiling, was backup, and was recording everything. Tony planned to show the video of the arrest to the family council.

The door concertinaed back; Eli Tanjung stepped inside; the lights, usually motion-sensitive but presently controlled by Aunty Jael, came up at half-strength. But the woman didn't cross to the junction box where the transceiver was located. Instead she hung by the door, nervous and uncertain, saying, 'Where are you?'

Tony sweated inside his cloak, gripping his gun, willing the woman to step towards the junction box. She called out again, her uneasy gaze sliding past Tony, coming back. He saw her expression change, knew that she'd seen the contours of his cloak. As he brought his gun up, motion exploded from shadows above him and the spidery hand collided with Eli Tanjung. She spun around and fell backwards, and the hand pinned her to the floor with its wiry limbs.

Tony pulled down his hood and stepped forward, aiming the gun at the young woman. 'Tell me why you are here,' he said.

Eli Tanjung stared up at him, started to say something, seemed to choke on the words. Then she was arching under the hand, balanced on her heels and the back of her head, pink foam spattering her lips, bubbling at her nostrils. Junot rushed forward, cradled her head with one hand and with the other gripped her jaw and forced it open and stuck his fingers inside, trying to clear her airway. But her face darkened and her eyes rolled back and she shuddered and fell limp.

Junot was straddling her, pumping his laced hands on her chest, when Lancelot Askia walked in.