Looking around for something to write with, I saw a message pad by the telephone. I went to it and wrote, Do you have a portable tape recorder? Then I pulled off that sheet and wrote my cell phone number on the next page.

When Lu Li read my question, she walked back to Fielding's study and returned with a Sony microcassette recorder, the type used for dictation. I put it in my pocket and led both women to the glass doors that opened onto the patio.

Maya followed us out but stuck close to Lu Li, who attached a leash to the dog's collar. About a hundred meters through the woods lay the University of North Carolina's outdoor amphitheater. On two previous occasions. Fielding had taken me there to talk.

"I know Andrew swept the house," I whispered to Lu Li, "but I still don't feel safe talking inside. I need to speak to Rachel alone for a few minutes. I want you to go back inside. Lock the doors, but leave Maya with us. We're going to walk through the woods to the amphitheater. We'll be back very soon. I have my cell phone, and I left the number on your message pad. If anything strange happens, call me immediately."

Confusion and worry wrinkled Lu Li's face. "You need Maya?"

"For cover. You understand? An excuse to walk out here."

She nodded slowly, then knelt, whispered something to the dog, and retreated into the house. I picked up the whimpering bichon and walked swiftly across the backyard to a narrow path that led through the woods. Rachel struggled to keep up as branches began to pull at our clothes.

"What are we doing?" she hissed.

"Keep quiet. I have to talk to you, and I don't think we have long."

I wasn't sure of the source of my fear, but I knew it ran deep. Without being aware of it, I had shifted the dog to my left hand and drawn my gun with my right.

CHAPTER 7.

"Ritter's here," said Corelli, his voice sounding tense in Geli's headset. "He's already got the laser trained on the front window."

"What's he hearing?"

"Definite sounds, but no conversation. Like one person moving around the house. They could be in one of the back rooms."

"Change position and put the laser on a back window. Hurry."

"Right."

Geli could hardly stay in her chair. Something was going down at the Fielding house, and she had only one way to know what it was. A minute passed, then Ritter's deeper voice said, "Nichts."

"You're not getting anything in back?" she asked.

"Nein."

"They know where the bugs are, and they've plugged them."

"Ahh," said Ritter. "How could they know that?"

"Fielding."

"That bastard," said Corelli. "He was always playing games with us."

Geli nodded. Around Trinity, Fielding had acted like an absentminded professor, but he was the sharpest son of a bitch in the place.

"They've probably left the house," Geli said. "Fielding and Tennant did that twice before. Walking Fielding's dog. I'm going to put a team in the woods."

"Nein," said Ritter. " Tennant will hear them."

''You have a better idea?"

"I'll go alone."

"Okay, but I'm setting up a perimeter. Tennant could be trying to run."

"I don't think so. It's a stupid way to run. And Tennant's not stupid."

"Why stupid?"

"When you run, you don't take women with you. You move fast and light."

Geli smiled to herself. "Tennant's not like you, Liebchen."

Ritter laughed. "He's a man, isn't he?"

"He's American and he was raised in the South. I knew guys like him in the army. Born heroes. They have this romantic streak. It gets a lot of them killed."

"Like the English?" Ritter asked.

Geli thought of Andrew Fielding. "Sort of. Now get going. Tell Corelli to cover the front."

"Ja."

Geli got out of her chair and began to pace the narrow alley between the racks of electronic gear. She thought of calling John Skow again, but Skow didn't want to be bothered. Fine, She'd call him when Tennant bolted, then see what the smug bastard had to say about not keeping the leash too tight.

CHAPTER 8.

I moved silently through the dark trees. Rachel sounded like a blind bear blundering along behind me. On a Manhattan street she probably maneuvered like a pro halfback, but the woods were alien to her. I slowed until she caught up, then told her to hold on to the back of my belt. She did.

When we were fifty yards away from the house, I said, "Do you believe me about Fielding now?"

"I believe you worked with him," Rachel said. "I'm not sure he was murdered. I don't think you are either."

I stepped over a fallen log, then helped her over. "I know he was murdered. Only two people at Project Trinity opposed what was being done there. Fielding was one, and now he's dead. I'm the other."

"Are you going to tell me about Trinity now?"

"If you're willing to listen. I think you understand now that it could be dangerous for you."

She sucked in her breath as briers raked her arm. "Go on."

"When you came to my house today, I was making a videotape to give to my lawyer. He was to open it if something happened to me. I never finished it. And the truth is, I'm worried about seeing tomorrow morning alive."

Rachel stopped in the overgrown track. "Why don't you just call the police? Lu Li clearly shares your suspicions, and I think there's enough circumstantial evidence to-"

"City police can't investigate the NSA. And that's who oversees Trinity."

"Call the FBI then."

"That's like calling the FBI to investigate the CIA. There's so much ill will between those agencies that it would take weeks to get anything done. If you really want to help, become my videotape. Listen to what I have to tell you, then go home and keep it to yourself."

"And if something happens to you?"

"Call CNN and The New York Times and tell them everything you know. The sooner you tell it, the safer you'll be."

"Why don't you do that? Tonight?"

"Because I can't be sure I'm right. Because the president could be trying to reach me as we speak. And because, as juvenile as it may sound, this is a national security matter."

Holding Lu Li's whimpering bichon in my left arm, I put my gun in my pocket and pulled Rachel forward. Forty yards on, I saw a deeper darkness ahead. The trees gave way like thinning ranks of soldiers, and then a man-made wall stopped me in my tracks. When my eyes adjusted, I saw the door I had known was there. I opened it with my free hand and led Rachel through. We emerged into a moonlit bowl, lined with cut stone.

"My God," she said.

The amphitheater looked as though it had magically been transported to the Carolina woods from Greece. To our right was the elevated stage, to our left a stone stairway leading up through the seats to the top row. Not far above that lay Country Club Road. The view down from the road was almost completely blocked by pines and hardwoods, but I could see the broken beams of headlights passing high above us.

I took Rachel's hand, stepped onto the stone floor, and led her to the edge of the stage. There I tied Maya's leash around a low light stanchion. While the dog sniffed an invisible scent trail, I set the tape recorder on the edge of the stage and depressed RECORD. "This is David Tennant, M.D.," I said. "I'm speaking to Dr. Rachel Weiss of the Duke University Medical School."

Playback gave me a staticky facsimile of my words. I looked at my watch. "We need to do this in less than ten minutes."

Rachel shrugged, her eyes full of curiosity.

"For the past two years, I've been working on a special project for the National Security Agency. It's known as Project Trinity, and it's based in a building in the Research Triangle Park, ten miles from here. Trinity is a massive government-funded effort to build a supercomputer capable of artificial intelligence. A computer that can think."

She looked unimpressed. "Don't we already have computers that can do that?"

This common misconception surprised me now, but when I went to work at Trinity, I hadn't known much better myself. For fifty years, science fiction writers and filmmakers had been creating portrayals of "giant electronic brains" taking over the world. HAL, the speaking computer of 2001: A Space Odyssey, had entered pop consciousness in 1968 and remained firmly embedded there ever since. In the subsequent thirty-five years, we had witnessed such a revolution in digital computing that the average person believed that a "computer that can think" was just around the corner, if not already within our capabilities. But the reality was far different. I had no time to go into the complexities of neural networks or strong AI; Rachel needed a simple primer and the facts about Trinity.

"Have you heard of a man named Alan Turing?" I asked. "He's one of the men who broke the Germans' Enigma code during World War Two."

"Turing?" Rachel looked preoccupied. "I think I've heard of something called the Turing Test."

"That's the classic test of artificial intelligence. Turing said machine intelligence would be achieved when a human being could sit on one side of a wall and type questions into a keyboard, then read the answers coming onto his screen from the other side and be certain that those answers were being typed by another human being. Turing predicted that would happen by the end of the twentieth century, but no computer has ever come close to passing that test. Using conventional technology, it's still probably fifty years off."

"Didn't that IBM computer finally beat Garry Kasparov at chess? I know I read that somewhere."

"Deep Blue?" I laughed, the sound strangely brittle in the amphitheater. "Yes. But it won by using what computer scientists call brute force. Its memory contains every known chess game ever played, and it processes millions of probabilities every time it makes a move. It plays very good chess, but it doesn't understand what it's doing. As a human being, Garry Kasparov never has to consider the billions of possibilities-many of them ridiculously simple-that the computer does. Kasparov's acquired knowledge allows him to make intuitive leaps, and to learn permanently every time he does. He plays by instinct. And no one really understands what that means."

Rachel sat on the edge of the stage. "So, what are you telling me?"

"That computers don't think like human beings. In fact, they don't think at all. They simply carry out instructions. All those TV commercials you hear about 'software that thinks'? They're bullshit. Serious AI researchers are afraid to even use the term artificial inteligence anymore."

"Okay. So what's Project Trinity?"

"The holy grail."

"What do you mean?"

"Everyone wants to build a computer that works like the human brain, but we don't understand how the brain works. Everyone concedes that. Well . . . two years ago, one man realized this didn't have to be the obstacle everyone thought it was. That we might be able to copy the brain without actually understanding what we were doing. Using existing technology."

"Who was this man?"

"Peter Godin. The billionaire."

"Godin Supercomputing?"

Now she'd surprised me. "That's right."

"They have a Godin Four supercomputer in a basement at TUNL, the Duke high-energy lab."

"Well, Godin is the man who conceived Project Trinity."

Rachel looked as though the accumulating details were starting to persuade her. "What kind of existing technology can copy the brain?"

"MRI.".

"Magnetic resonance imaging?"

"Yes. You order MRI scans every week, right?"

"Of course."

"There's a lot of information on those scans, isn't there?"

"More than I can interpret sometimes."

"Rachel, I've seen MRI scans that contain a hundred thousand times the information of the ones you see every day. A hundred thousand times the resolution."

She blinked. "But how can that be? How much more can you see?"

"I've seen reactions between individual nerve synapses, frozen in time. I've seen the human brain working at the molecular level."

"Bullshit."

Any doctor would have said the same. "No. The machine exists. It's sitting in a room ten miles away from us right now. Only nobody knows it."