Rachel was shaking her head. "Why did you become a doctor rather than a physicist?"

She couldn't stop being a shrink. Or maybe she was just being a woman. "After Hiroshima, my dad led a troubled life. Edward Teller was gearing up to build the hydrogen superbomb. Oppenheimer opposed it. So did my father. Dad requested a transfer. General Groves didn't want to release him from weapons work, but they agreed to give him a more technical job, one more removed from the actual warheads. They moved him to the national lab at Oak Ridge, Tennessee."

"Why didn't he just quit altogether?"

"Eventually he did. But this was the Cold War. There were different kinds of pressure then. Oppenheimer was persecuted for years for his opposition to the hydrogen bomb. Dad also met my mother at Oak Ridge. Things were better there. They had my brother. I was born much later. An accident, really." I smiled at the memory of my parents revealing this fact to me. "I grew up in Oak Ridge, but when I was a teenager, Dad quit nuclear physics and moved us to Huntsville, Alabama, so he could work on the space program."

"I still don't see the medical connection."

"My mother was a pediatrician in Oak Ridge. She did a lot of good. It didn't take a genius to see that she was a lot happier in her work than my dad had been. That's what influenced me."

I glanced down at the phone, willing it to ring again. "Last night, I only told you part of the truth. When the president offered me this position, it felt oddly like poetic justice. I was being given the opportunity my father never had at Los Alamos. The chance to exercise some control over a great undertaking that was likely to change the world forever. For good or evil. I sensed that that the day I visited the Oval Office, and that's what put me here."

Rachel took a deep breath and slowly blew out the air. "It's all real, isn't it? Trinity, I mean."

"Yes. And I'm damned glad McCaskell called me back. We need the president badly."

I stood up, half wanting to replay McCaskell's message, but a wave of fatigue rolled through me. I hoped it was just exhaustion, but then the familiar high-pitched ringing began in my back teeth. Remembering I had no amphetamines left, I took a can of Mountain Dew out of the fridge, popped it open, and drank a long pull for the caffeine.

"David?" Rachel was watching me strangely. "Are you all right? You look shaky."

"I may go out," I said, taking another gulp of the soda.

"Go out?" Her eyes widened. "Narcolepsy?"

She'd never witnessed one of my episodes. As I nodded, a shadow seemed to pass over my eyes. It left me with a vague feeling of threat, as though someone were in the room with us, there but unseen. "I'm missing something," I thought aloud.

"What are you talking about?"

An image of Geli Bauer came into my mind. "We're in danger."

Rachel looked worried, more about me than any external threat. "What kind of danger?"

"There's something about the way all this is happening. Godin giving us time off… my chart being stolen from your office… McCaskell's call. I'm missing something, but I'm too tired to think of what."

"I thought McCaskell's call was good news."

"It is. It's just…" As drowsy as I was, I felt a desperate need to have my gun in my hand. "I want you to do me a favor. Wait here for two minutes."

"What?" Worry darkened her eyes. "Where are you going?"

"To my neighbor's house." I hurried to the back door.

"David! What if you pass out?"

"Don't answer the door!" I called. "But if the phone rings, answer it and say I'll be right back."

I ran outside and crashed through the thick hedges that bordered the backyards of the houses on my street. I sprinted the length of three backyards, then cut back through the hedge behind a neighbor's utility shed. I had slipped out of my house last night about 2 A.M. and I had hidden Fielding's box beneath it. Inside the box were Fielding's electronic gadgets, my partially recorded videotape, Fielding's letter, and my pistol. I got on my knees and retrieved the box, then crawled back through the hedge and sprinted back to my own yard. By the time I reached it, I felt like a drunk running through an unfamiliar city.

Rachel was waiting just inside the back door. "That's the stuff from last night," she said. "Why do you need that?"

I tilted the box so she could see the gun.

She stepped back. "David, you're scaring me."

"You need to get out of here. You'll be fine for the time it takes me to tell my story to McCaskell." I set the box on the floor, put the gun in my waistband, then led her to the front of the house. "Spend the rest of the day somewhere public, like a mall. Don't go home until you hear from me."

She pivoted and stopped me from pushing her toward the door. Her assertiveness seemed to bring us eye to eye. "Stop this! You're so out of it right now you could shoot yourself by accident."

I started to reply, but my words went spinning off into the dark edges of my mind. I would be unconscious in less than a minute.

"I'm about to go under."

She grabbed my arm and dragged me into the hall, looking for a place to lay me down. I pointed to the door of my guest bedroom. Sensing that I was about to faint, she rushed me through the door and let me fall face-down across the mattress. "Do you have any medication?"

"I ran out."

Her footsteps moved away. I heard cabinet doors banging, then Rachel's voice talking to herself. When the voice seemed closer, I managed to roll over. There was a dark silhouette in the doorway.

"Coffee's brewing,” Rachel said. "You're still awake?"

"Sort of."

She watched me like someone observing an animal during an experiment. "There's no food in your kitchen, nothing but rock-hard saltines. When was the last time you went to the market?"

I couldn't remember. The last few weeks had been an endless parade of hours working with Fielding on experiments I barely understood.

Rachel sat on the bed and put her fingers against my carotid artery. Her fingertips were cool.

"I was like that for a while," she said, looking at her watch. Her lips moved slightly as she counted pulse beats. "After I lost my son. Not going to the market, I mean. Not paying bills. Not bathing. I guess it takes a man longer to get back to those kinds of things. In the end, I used those small chores to enforce some order in my life. It kept me from going completely mad."

I felt my lips smile. I liked that she didn't let psychiatry get in the way of using words like mad. I also liked the way her fingers felt against my neck. I wanted to tell her something about her touch. It reminded me of someone, but I couldn't think who…

"When's your birthday?" she asked.

I couldn't remember.

"David?"

A black wave rolled over me, covering me in darkness

I'm walking up a suburban sidewalk, studying the perfect houses in their perfect rows. It's Willow Street. I live on Willow -sleep on it, anyway-but it has little in common with the street I lived on as a boy. On Willow Street, I don't know my neighbors well, and some not at all. The NSA told me not to make friends, and that has turned out to be easy. On Willow Street, no one makes an effort. In Oak Ridge the houses were smaller, but I could name everyone who lived in them. My little neighborhood was a world unto itself, filled with faces I knew like those of my own family. On Willow Street the children stay inside more than outside. The fathers don't cut the lawns, hired men do. In Oak Ridge, the fathers cared for their lawns like little fiefdoms, spent hours discussing various mowers and fertilizers with each other.

I walk around a curve and see my own house. White with green trim. From the outside it looks like a home but it's never felt like home to me. A black Labrador retriever lopes across the street without its master, a rare sight here. A Lexus rolls toward me, slowing as it passes. I wave at its driver, a tall, imperious woman. She stares at me as if I'm a dangerous interloper. I cross the street and walk up to my front door.