There was a slipcover on one of the sofa pillows. I took it off the pillow, then put the Ziplocs inside it and handed it to her. "Be very careful with those."

"You're preaching to the choir."

I squeezed her arm. "Thank you. Now, go."

She didn't go. She stood on tiptoe and kissed me gen¬tly on the lips. "Be careful. Please, please be careful."

As I stared, Rachel slid the slipcover under her blouse, then walked to the foyer. I heard the front door close softly. Through the front window I watched her get into the taxi. The cab pulled into Lu Li's driveway, then backed out and rolled up Gimghoul Street.

I went out to my car, pulled up to Fielding's garage door, and tapped my horn. Lu Li opened the door from inside, then closed it behind me.

She pulled open my passenger door and set her hus¬band's cardboard box on the front seat. I reached across it and gripped her wrist, my eyes boring into hers.

"Tell me the truth, Lu Li. Do you know what they're trying to build at Trinity?"

After several seconds of eye contact, she nodded once.

"Don't ever tell anyone that," I warned. "Never."

"Me Chinese, David. Know what can happen."

For an instant I flashed back to her standing silhouet¬ted in the patio doors, a target awaiting an assassin.

"Come with me," I said suddenly. "Right now. Just get in with your dog and we'll go. I'll keep you safe."

A sad smile touched her lips. "You good man. Like Andrew. Don't worry. I already make my own arrange¬ments."

Arrangements? I couldn't imagine what these might be. I didn't think she knew anyone in the States. "What are they?"

She shook her head. "Better you don't know. Yes? I be okay."

For some reason, I believed her. The revelation that Lu Li had not been rendered helpless by her grief made me ask one more question.

"In his letter, Andy told me that if anything happened to him, I should remember his pocket watch. What's so special about that watch?"

Lu Li studied my eyes for what seemed a long time. Then, in a nearly inaudible whisper, she said, "Not watch. Fob."

"Fob?"

"Watch fob."

I closed my eyes and pictured Fielding's watch. It was a scarred but precious heirloom, and at the end of its chain was a small, diamond-shaped crystal.

"The crystal?" I asked.

Lu Li smiled. "You smart man. You figure it out."

Geli Bauer was on her feet, pacing the control center and shouting into her headset at John Skow. She'd never lost her temper with him before, but without Godin backing her up, Skow was proving maddeningly obstinate.

"Haven't you heard a word I said? Can't you see what's happening?"

Skow answered in a condescending voice, "This is what you've told me. Dr. Tennant and Dr. Weiss visited the grieving widow and walked her dog. Dr. Weiss kissed Tennant, then she went home in a cab."

Geli closed her eyes and tried to suppress her anger. "Tennant pulled into the garage and closed the door before he left the Fielding house. He obviously took something that he didn't want us to see."

"That's possible," Skow said. "But as far as you can tell, he's headed home now. What's the problem?"

"We couldn't hear a damn thing! They plugged the bugs, same as they did at Tennant's house. And Weiss left her Saab at Tennant's house, instead of taking the cab there to pick it up. Why would she do that? Tennant might be planning to run or even to go public. Maybe both."

"I think you're projecting your own paranoia onto him."

"Ritter heard them talking about MRI side effects."

"That's small potatoes. You couldn't know that, of course. The Super-MRI unit is Tennant's pet ethical con¬cern, and it's got nothing to do with the central issue."

"But they talked for ten minutes before that. And Ritter thinks he saw a tape recorder."

Skow sighed. "What would you have me do about that?"

"Take them out."

The NSA man caught his breath. "Did I hear you cor¬rectly?"

"You know you did. We have to assume Weiss knows the full details of Trinity and about Tennant's suspicions regarding Dr. Fielding's death."

"Dr. Weiss is a private citizen who's broken no law."

"If you won't take them out, then bring them in for interrogation with prejudice."

The resulting silence seemed interminable. Then Skow said, "Do you have someone following Dr. Weiss's cab?"

Ritter was covering Weiss. "My best man. He could easily stage an accident."

Skow's voice, when it came, was like shaved ice. "Listen to me, Geli. Your man will follow the cab to Dr. Weiss's residence, then break contact. He will not let her see him. He will not even breathe hard in her direction."

"What?"

"Call off your dog. And your team on Dr. Tennant will follow him to his residence and set up a static sur¬veillance post as per normal procedure."

Why the hell would somebody keep a cobra's fang? She wanted to go to the storage room and check the actual objects against the list, but she was too pissed off to deal with that.

She had always worked with incomplete information at Trinity. It hadn't bothered her much. The army was good training for that. You could guard a building for twenty-four hours without knowing whether it contained nuclear bombs or cases of underwear. But now there was too much she didn't know. The mystery at the heart of Trinity was taking control of everyone and everything around it. Yet there was nothing she could do. She had to talk to Godin, and he was incommunicado.

Faced with this impasse, she called Ritter Bock and told him to break contact with Weiss. The taciturn young German was needed back at the control center. Skow had ordered her to calm down, and Geli knew only one way to do that. She needed to take some orders rather than give them.

Dreamless sleep evaporated in a rush of pounding blood and the memory of Fielding lying dead in his office. Sunlight knifed through a crack in the curtains. I had sur¬vived the night, but still I reached beneath my pillow for my.38. Only then did I slap the top of my clock radio, killing the alarm.

My phone had not rung during the night, so the presi¬dent hadn't tried to reach me. I checked my answering machine in case I had slept through a call, but there were no messages. Trying not to think about the implications of this, I dialed Lu Li Fielding's house. A machine answered. The taped message still had Andrew's voice on it, brimming with humor. Hoping Lu Li was a hun¬dred miles from Chapel Hill by now, I hung up and car¬ried my gun into the bathroom, then locked the door behind me.

I shaved quickly. A surveillance car had been parked nearby when I got home from Fielding's house last night. It pulled away as I approached. After removing the sensitive items from my trunk, I called Rachel at home to be sure she'd made it. Then I lay awake for two hours, lis¬tening for the sounds of a break-in and thinking of Fielding's pocket watch. It had a dull gold case, worn from rubbing, and a yellowed face with Roman numer¬als. Not the watch, Lu Li had said. The fob. I'd asked Fielding about the crystal on his watch chain once. He told me a Tibetan monk had given it to him near Lhasa, promising it would ensure an unfailing memory. Fielding belly-laughed when he told me that story, but I hadn't gotten the joke. Now I did.

One new computer technology perfected by the Trinity team was holographic memory storage. Rather than stor¬ing data in microchips, Trinity engineers stored it as holo¬grams within the molecules of stable crystals. Using lasers to read and write data, they could store enormous amounts of information within the crystal's symmetrically arranged atoms. The crystals I had seen in the Trinity holography lab were the size of NFL footballs, but I saw no reason that a smaller one could not be used. Like the one on Fielding's watch chain.