Keiran has to admit that on some level Danielle is right: part of him is glad to be pursued by the law. He has spent years hacking into dozens of corporate and government systems, but he has never been able to justify actually using his access before. It has always been too risky: every abuse of a compromised system might be noticed and somehow be tracked, could be the mistake that leads to his downfall. But now he has an excuse to flex his virtual muscles, use all the dormant authority he has accumulated over the years, and the exercise of raw power feels good.

First he needs anonymous money. Easy enough. He occasionally advises a group of Russian credit-card hackers on technical matters: in exchange, he has access to their "platinum list" of high-limit, high-volume credit card numbers, the kind for which a single hundred-dollar charge is likely to go unnoticed. Hacked from some upscale travel agency in Chicago, apparently. He uses thirty such credit cards to rent a nearby post office box, then purchase and post to that box four anonymous Virgin Mobile cell phones, two hundred dollars' worth of phone cards, and twenty cashier's checks for a hundred dollars apiece.

After money, identity. In the space of forty minutes, he arranges for three brand-new Social Security cards and California drivers' licenses to be mailed to the post office box he just rented, in the names of Sarah Crawford, Julian O'Toole, and Parvati Rumanujan. Keiran and Danielle's new licenses feature photos from Mulligan's digital camera that display their new looks, touched up to look entirely unlike the pictures in today's newspaper. He goes back to the Russian credit-card list and throws in a secured MasterCard for each of them, with thousand-dollar limits, in the same false names.

"Aren't you worried they could find the mailbox?" Danielle asks, when he explains the outcome of his cyberspace pillaging. She has been sitting quietly beside him the whole time, shoulder-surfing, although he doubts she or any other non-hacker could have followed a tenth of the work he just did.

"They don't know to look for it. And we have to make sure it stays that way. Remember, no phone calls home, no checking email, don't even visit any of your favourite Web sites. We're only omnipotent for as long as we're invisible."

"If you can do this, why haven't you ever just taken ten million dollars from some bank and retired?"

Keiran shakes his head. "Taking money is a violation of LoTek's Law. Always be invisible. Creating a new identity is invisible hacking. If you do it right, no one will even notice. But stealing an identity, or stealing money especially, that's very visible. I could probably steal a million dollars a week from Social Security if I wanted to. Maybe I could break into a bank. Maybe not, they're a lot sharper about security then the government. But even if I did, money is a zero-sum game, there is no way to steal significant amounts without being noticed. More than a few hundred dollars will trigger their alarms, alert their forensic accountants, get them angry. And once they're angry, they will track you down. Once they start they usually win. Authorities are stupid, but they're very big, very resourceful, very persistent. If they find out I exist they'll squash me like a cockroach. But if you don't even know you have roaches, you never call the exterminator."

"It's scary that you can do this," Danielle says.

"Good. Because right now we need to be frightening."

"I can't believe all these systems are so insecure that anyone can break into them."

Keiran smiles. "Not just anyone."

"Sorry. I didn't mean to imply you were mortal."

"Not what I meant. I have a secret weapon. Shazam."

Danielle looks at him. "I've heard of that. I've used it, I had it on my computer in Bangalore. I thought it was a program for downloading music, like Napster or iTunes, right?"

"In a way. But Napster had central servers, and a business, and an address that record companies could send their lawsuits to, so they got shut down. Shazam is just a piece of software. People install it, and it looks around the Internet until it finds other computers with Shazam. It can be used to share anything, but yes, almost always music. It's very popular. More than seven million copies in active use. It's free and open source, so people can look at the software themselves and see that there's no hidden agenda, no spyware, nothing that will take over your computer. And it works. Most open source software usually doesn't quite. I'm very proud of it."

"You hid something in it."

Keiran nods, pleased. "A tiny little buffer overflow, obfuscated inside one of the trickiest and dullest parts of the code. Anybody can look at it, but in all these years, nobody's analyzed it in enough detail to find the bug. Like Shadbold said when he let us go. You can rely on people to do things. It would take a great programmer several very tedious hours to analyze that piece of code and find the bug, and none of them can be bothered to waste their time like that."

"And that little thing lets you take it over?"

"It's like a tiny lock, with an insanely complicated key, that opens up their whole computer to me. I can own any box that runs Shazam. And you'd be amazed where it runs. Seven million copies. Police stations, the ATF, the White House, foreign militaries, you name it. Secretaries and IT grunts around the world use it to steal music from the Internet on work time. And then I use it to steal their machines. Places with seriously organized IT security ban it and make the ban stick, but you've worked in offices, you know how often those rules are followed in the real world. Maybe one company in ten actually enforces them. Kishkinda being one of them. Not a single instance running there. But there's one machine on the Justice International network that proved very useful indeed."

"And once you've got access you can just turn around and get me a driver's license and Social Security card like that? It's that easy?" Danielle asks.

"No. Shazam is just a beachhead. I have to work out what to do with the access, where their databases are, how to break into the rest of their network, how their homegrown programs work. It isn't easy. When I broke into Social Security, two years ago, it took me three weeks at fifteen hours a day to work out how to issue a new card and fix the audit trail to fool their safeguards. But once that work's done, well, today I could fill a city with people that don't exist."

"How long has Shazam been out there?"

Keiran pauses to think. "Almost five years. Tell you the truth, it'll be obsolete soon, it's already being replaced by BitTorrent and the like."

"You never told me about this when we dated," Danielle says accusingly.

He looks at her incredulously. "You can't be serious. We're talking about the hacker Holy Grail here. I've never told anyone except a few of my hacker friends. Mulligan, George, Klaupactus, Trurl. Everyone else just thinks I'm naturally godlike. You're the first non-hacker I've ever told. You should be flattered."

"I'll try to remember," Danielle says, but she sounds mollified. "So if your Shazam network is so great, why can't you stomp this P2 guy?"

Keiran opens his mouth – and closes it again. He is not accustomed to being pitted against a superior hacker. But he has to admit that truth. Keiran could have tracked Jayalitha's phone call to Danielle; he tunneled into America's major phone companies years ago, and has at least read-only access to most of their corporate databases. But he could not have worked out overnight which Los Angeles hotel she was in. On Keiran's advice, Danielle had showed up at the hotel without making a reservation, and yet P2 had found her. She couldn't have been followed, or he wouldn't have waited until midnight, or bothered calling her hotel to verify her presence. P2 must have broken into the rental-car company's tracking system, located Danielle's car, and then literally hacked into every one of the dozens of nearby hotels.

It seems like a little thing, compared to creating new government identities, but hacking is a time-consuming art. It can take Keiran days or even weeks to crack a new network, even with Shazam's seven million machines on his side. P2 found Danielle in a few short hours. Maybe he just got lucky – but three months ago, when Shadbold's thugs kidnapped him from his London flat, they were sent there by P2, who found Keiran in a matter of minutes despite Keiran's many paranoid precautions.

Those two extraordinary feats cannot both have been luck. The only logical conclusion to draw is that Keiran is overmatched. Either P2 has been around forever, and has a finger in every electronic pie on the planet, or he knows some extraordinary new exploit that gives him the power to immediately hack into virtually any system. For safety's sake, Keiran has to assume that P2 has at-will access to every computer, database, network and satellite in the known world. Other than Shazam.

"Let me put it this way," he says. "I might have the Holy Grail, but P2 appears to have a direct line to God himself."

"Great. Just great. When does my new ID get here?"

"A few days."

"We're supposed to stay here until then?"

"No," Keiran says. "We need more to work with if we're going to catch P2, and we need it fast, this hunt is sure to be a major time sink. You remember the corrupt police who chased you last night?"

"Like I was about to forget," Danielle says drily.

"Well. Tonight, we chase them."