'What is it?' Peri asked point-blank.

The Doctor hesitated. 'Not yet, Peri. Not yet.'

'Well,' Peri said helplessly, 'be careful.'

'One more thing,' said the Doctor. 'It's extremely rude to eavesdrop on other people's phone conversations.'

'Aw, shoot shoot,' said Mondy. 'No way!'

He tossed the tape deck to me and scooted his seat forward, starting up the engine. 'What about your equipment?'

I said; craning my neck. Bob's study was dark.

'Never mind that,' said the phreak. 'I swiped it from an FBI tap. They can have it back.'

'Wait,' I said, just as he pulled out. He slammed on the brakes and glared at me. 'I want to talk to them.'

'You've gotta be kidding,' he protested.

'Let me drive.'

'No!' He was already out of the driver's-side door.

'I'm serious!' I said, as we ran around the bonnet, changing sides.

'Not a chance!' he insisted, sliding into the pa.s.senger seat.

'It's gotta be done!' I said, grabbing the steering wheel.

Bob's Pontiac roared out of the little court like a rogue elephant. We followed, trying to hang back as they wound through a series of suburban streets. But we must have been pretty conspicuous: they kept speeding up and slowing down, and I could see Peri looking back at us. Once they took an obviously random turn, and came back down the side street a minute later to find us waiting for them.

Bob got the Pontiac onto 495 and shot away 'Oh s.h.i.t!'

shouted Mondy, as I followed them onto the Beltway, flattening the accelerator Compared to Bob's car, the Escort was like riding a lawnmower. 'If you wreck my car Peters, I swear I'll swap your home number with a cathouse!'

'Relax,' I said. 'We're not Kojak and neither are they.'

'This had better be worth it.'

'Swan's got something even Uncle Sam doesn't know about. And these guys want it. It's the story of the century.'

'Oh, quit exaggerating,' grumbled Mondy.

'Think about it. It's got to be something she can use for hacking, that's all she's interested in. Maybe it's a program for breaking into military systems. Or some new protocol for connecting computers. Or a successful artificial intelligence!

Isn't your curiosity piqued?'

'Maybe Swan is a Russian agent and it's a KGB supercomputer,' said Mondy sourly.

's.h.i.t, we're losing them.'

'Will you slow down!'

'I will if they will. Relax, he won't get far before he gets stuck in the traffic like everyone else.'

It was only a few minutes later that we both wound up in the queue of cars creeping around DC, b.u.mper to b.u.mper. I smoked and thought while Mondy fidgeted. What if Bob and Peri were Russian agents, I thought? Come on, I told myself, they're just a couple of kids. But what about the Doctor? What if the English guy was working for a foreign power, conning a couple of unsuspecting hackers into feeding him secrets?

Visions of Kim Philby danced in my head.

We crawled through Beltway traffic for half an hour, keeping Bob's car within sight, but never quite catching up with it. It must have been the slowest car chase in history.

In the end, we pursued them to Tyson's Corner, a giant mall in McLean. Bob and Peri wove through the Christmas Eve crowd in the parking lot, trying to lose us in the toing and froing of cars. Tyres squealed as cars braked, trying not to back out onto us as we continued our slow-motion pursuit.

They finally managed to shake us off after five dizzying minutes when we got stuck behind a dingle. 'It's no use,' said Moody. 'They'll burn on out of here and we'll never see them again.'

'I think they came to Tyson's for a reason,' I insisted. 'I want to look for them inside the mall.'

'Have you been been in there?' said Moody. in there?' said Moody.

Miraculously, we'd found a parking spot. 'I'll tell you what,' I said. 'You check the payphones. If you see them, gimme a page. Got the number?'

'Memorised,' he said We jumped out and hurried through the rows of cars into the vastness of Tyson's. Moody obviously knew the mall better than I did he immediately vanished into the crowds, heading for the payphones. He'd know where every phone was.

I looked for computer stores, jogging through the mobs of shoppers. I reckoned Bob would want to stock up on equipment after having to make a run for it. But maybe he just wanted to get thoroughly lost.

After ten minutes, Mondy paged me. 'I've got them,' he mumbled. 'I'm right near them. He gave me directions to another row of payphones. And he gave me the number of a phone right next to them.

I wish I could have seen Bob and Peri's faces when the phone next to them rang. (Mondy did, of course he was standing just a few feet away. ) It rang several times before Bob picked it up.

'h.e.l.lo?'

'Bob, please don't hang up. My name's Charles Peters.

I'm a journalist. Your "little expedition" into the TLA building got me interested.'

'Jesus, does the whole world know about it?'

'Excuse me, but we have to leave now,' said Peri, tugging at his arm.

'It's OK. Swan doesn't know who you are. All I want is the story I can guarantee your anonymity.'

Peri shook her head. Bob said, 'Over the phone I don't think I can tell a real journalist from an FBI agent. Bye.' He hung up. They both looked around, wondering where I was. I must be watching them, right? They couldn't know I was in a completely different section of the mall.

Mondy called me back. (Don't ask me how he knew what number to dial.) 'They're heading back to their car.'

I met them at the door to the parking lot. Our eyes met as I strode towards them. They knew at once I belonged to the voice they'd just heard. Bob actually said 'Yikes!' when he saw me coming. He froze, probably expecting me to pull a gun and order him to do just that. Peri instinctively ducked behind him.

I held up both hands, trying to look harmless: just an ordinary guy in jeans and a sweater, not too tall, not too muscular, not too threatening. 'I'm not the FBI I just want to talk,' I said.

'How did you find us?' demanded Bob.

I grinned. 'I'll tell you all about it. Let me come along for the ride.'

Bob said, 'Mister, you've got to be joking.'

Peri put a hand on his arm. 'I think we'd better,' she said.

'Sounds like he already knows everything.'

Behind them, Mondy gave me a wink, and then joined the flow of late-night shoppers. His work here was done.

I kicked a bunch of c.r.a.p off the back seat and squeezed into Bob's car, obliged to hold a spare disk drive on my lap to make room for myself. They murmured to one another in the front seat, watching me in the rear view mirror.

'The Doctor's gonna kill us,' Bob said.

Peri shook her head. 'The Doctor's gonna kill him him.'

We headed back to Bob's apartment in an awkward silence. When we got inside, Bob lurked about like a spy, pulling down the blinds, running a fingertip behind the Magritte print. At last, apparently satisfied, he sat down on the sofa beside his touch-tone phone, plucked its cord from the wall, and replaced it with a battered old rotary-dial phone from his bottomless bag of goodies.

Despite all the secrecy, Bob couldn't resist explaining how they and the Doctor were going to make contact. 'We've each got one number from a looparound pair,' he told me. 'The phone company sets up these lines so they can run tests. You give the other person one number in the pair and you dial the other one, and then you can talk to one another over the test line for free. At night, anyway, when the telco's not actually using them. It's convenient when you don't want to give out your phone number.'

He dialled the number and held the receiver up to my ear.

There was no sound of ringing, just a click; and then a high-pitched electronic beeeeeep which sounded like the Emergency Broadcasting System. After perhaps ten seconds, the tone cut out for a moment, then started again. 'That's the singing switch,' said Bob. 'When the tone stops, you know someone has dialled the other number in the pair.' He settled back on the sofa, arms folded behind his head, the receiver squashed against his ear by the inside of his elbow.

'What if Swan knows about the, uh, looparound pairs?'

Peri said. Her voice became pinched and high when she was stressed, often sounding as though she was about to burst into tears. 'You made it sound like she knows everything.'

'Swan thinks the phone system is for kids,' said Bob.

The tone was loud enough that I heard it cut out from across the room. Bob sat up at once. 'h.e.l.lo, Doctor, can you hear me all right?' Peri put her ear close to the receiver so she could overhear their conversation. 'We've got a little problem,' said Bob. He and Peri both looked up at me as Bob filled the Doctor in on my presence. 'Are you sure? All right OK, I'll tell him.'

Bob handed the phone to Peri. 'Why can't we see you?'

she said. 'Well, how's that going to make it any worse?'

Bob sat down on the arm of the easy-chair. 'The Doctor wants to see you you,' he told me. 'Right now.' Behind him, Peri put the phone down with an exasperated sigh. 'Go to a payphone. If you're sure n.o.body's following you, call this number. It's another looparound pair.' He rolled up my sleeve while I was reaching for my notepad, and inscribed a number in ballpoint on the skin of my arm. 'The Doctor will give you instructions on how to find him. OK?'

'I guess you're not coming along?' I said.

Peri, slumped on the sofa, said, 'I guess we're not.'

30.

One.

Sheer luck led Smith Swan to discover the intruder on her system that Christmas Eve. With no family to visit, Swan routinely worked through the vacation; she liked to have the company's computer resources to herself. That evening, long after everyone else had gone home, Swan was still in her office on the third floor of the TIA building. A single strand of purple tinsel was taped to her office door in concession to the season.

Swan was about to send an electronic message to one of her co-workers elsewhere in the building, and so wanted to see if they were still logged on to the machine or had gone home for the holidays. She typed in a short command: who

And the terminal responded:

sswan pts/0 Dec 24 17:48 jsmith pts/3 Dec 24 19:55 hostmast pts/5 Nov 24 04:07 uucp pts/2 Nov 24 04:05 root pts/4 Dec 24 00:01

Swan stared at the list of users for a moment. Who the h.e.l.l was jsmith? Only members of the research team had access to the mainframe. (The other 'users' were automated programs. ) Swan did some checking. No-one was dialled into the computer, so her intruder wasn't coming in via a modem. He must have logged in remotely, from another machine on the ARPAnet. Either he had set up an account on her machine, or someone had given him one. He had come from - - Where had he come from? There was no entry for him in the file that automatically logged visitors to the machine.

Swan kicked jsmith off and deleted the account. She did a quick check of the computer's files, rea.s.suring herself that the intruder had done no damage. He could only have been logged in for a short time before Swan spotted the illicit access.

Swan made it her policy to tolerate just a little joyriding in the TLA system. After all, she'd spent years doing exactly the same thing herself seeing what was out there, making her own map of the net. She kicked hackers off her system, no negotiation and no second chances, but she generally didn't hand out punishments. The intruder hadn't expected anyone to be around on Christmas Eve. She smiled. She'd probably just given some college boy a good scare.