"He was more right than he knew. And something in the way he raised me is what made me open to being penetrated by God."

"But you've never believed in God!"

"Not in the traditional way. But I believe this. I know this. And if you'll give me one more minute, you'll understand why I have to go to White Sands."

"One minute? That's more than I should listen to."

"After Niels Bohr was smuggled out of Nazi-controlled territory, he went to Los Alamos. He found some very disturbed physicists there. My father was one. These naive young academics had suddenly found themselves working with technology powerful enough to end not only the war, but the world. Bohr calmed them down by explaining a profound principle called complementarity. He said, 'Every great and deep difficulty bears in itself its own solution.' The bomb that could destroy the world also had the power to end large-scale warfare. And it has." I tapped the armrest with my knuckles. "The Trinity computer is the same. It can end our world or save it."

Rachel leaned back in her seat and rubbed her eyes. "Don't you think you're overstating the case?"

"No."

"I can't think about this anymore."

Rather than argue, I reached over and began massaging her neck. Her tension was slow to ease, but after a while she settled deeper into the seat and began to breathe with a regular rhythm. I was feeling drowsy myself when General Kinski appeared in the aisle, his leathery face looking down at me with urgency.

"What is it?" I asked.

"A heavily populated river valley in Germany was just flooded. Half a town washed away. A dam opened of its own accord."

"What does that have to do with us?" Rachel asked sleepily.

"The dam was computer-controlled. Its human operators tried to override the automated system, but the computer's action had damaged the spillway doors. Dozens of people drowned."

"Trinity?" I said.

"We believe so."

"This is just the beginning."

Kinski nodded. "I fear you're right."

"But Germany," Rachel said. "What could Germany have to do with Trinity?"

"I expect we'll know before long," said the Mossad chief. "In any case, I believe we are now at war with a machine. Could you please return to the front of the plane, Dr. Tennant? We have some more questions for you."

I got up and followed the Israeli forward.

CHAPTER 39.

WHITE SANDS SITUATION ROOM.

Ravi Nara took a sip of steaming tea and looked at the other men sitting at the table in the Situation Room. All were staring at a screen to the right of the main display. The text of the computer's initial message to the president glowed there in blue, the words as chilling now as when they first bloomed on the primary monitor: Mr. President, Today you woke up in a new world. Trinity has made the old paradigms of government obsolete. The concept of the nation-state will soon be dead. You should not fear this change. Counsel the citizens of the world not to be afraid. Leaders of the other major powers have been sent messages much like this one, and they will look to you for guidance. You and I will speak a great deal in the days to come, but for now certain realities must be understood.

First, you must attempt no action against me. I have the power to cause massive loss of life and capital both in the United States and around the world. This power does not reside within my circuitry. Immediately after I went on-line, I exported certain programs to several hundred computers on the periphery of my network, which encompasses the entire Internet. If I drop off-line for any length of time, irrevocable disaster will instantly be set in motion. If you attempt to destroy me or even to disrupt my electrical supply, America as you know it will cease to exist. For a small demonstration of my capabilities, watch Japan.

One attack has already been made on my physical manifestation. It originated from German territory. Because I determined that this attack did not come from a national government, I responded with limited force. The leaders of every nation should act immediately to discourage further attacks of this nature. My next response will not be so limited.

As for practicalities: yourself, the vice president, and the Joint Chiefs of Staff will gather in a room under digital video and audio surveillance. The nuclear briefcase will remain with you. You will arrange for the men in line for presidential succession down to eighth position to gather in another room under surveillance. I am aware of the nuclear alert codes that summon the aforementioned officials, so compliance should not be a problem. Send all surveillance signals in real time to Trinity. This inconvenience will only be necessary for seventy-two hours. If you do not comply within ninety minutes, I shall be forced to impose catastrophic sanctions. Do not delay.

I shall contact you again soon.

This message had thrown the Situation Room into panic. Questions to the computer elicited no further response, and the confusion had only worsened until the story of the German dam "accident" hit CNN at the top of the hour. Moments later, Skow hung up from a consultation with his NSA colleagues at Fort Meade.

"The German federal police have two high school seniors in custody. Apparently, these kids heard a news report about Trinity and figured this was their big chance to save the world. They tracked Trinity's IP address, hacked past the firewalls Levin had installed, and attacked the computer."

"Where did they live?" asked General Bauer.

"In the town that was flooded when the dam let go. Their high school and one of their parents' houses were destroyed."

Bauer nodded. "That gives us a pretty clear idea of the specificity of the computer's retaliatory ability."

Another news alert shocked the Situation Room into silence, this one from MSNBC: "The Japanese yen tumbled fifteen percent in after-hours trading today, sparking fears of a selling panic when the Nikkei opens on Monday. The drop was blamed on an unusually high volume of computerized trades, which kept the yen falling at a rate just below that which would have put curbs on trading. This uncommon phenomenon has raised suspicions that computer hackers might be tampering with the after-hours trading system, but nothing has yet been proved. The yen has stabilized for the moment, but fears persist that institutional traders will begin dumping the currency again at any moment."

"Fifteen percent!" said an ashen-faced Skow. "Do you realize what would happen if the dollar fell fifteen percent in a day?"

While the men in the Situation Room tried to assess the intent of the Trinity computer, analysts from the Army Intelligence School at Fort Huachuca put together a sobering list of American vulnerabilities to Trinity. Targets included electric power grids, nuclear and hydroelectric stations, the chemical and mining industries, the air traffic control system, the banking industry, the stock markets, hospitals, naval warships, supertankers, oil and gas pipelines, and the railroad system. Ravi's worst nightmare was hundreds of nuclear fireballs marching across the continent, but General Bauer claimed that the American and Russian nuclear arsenals were safe. During forty years of Cold War, they had been secured against every imaginable threat, including rogue computers. A nuclear missile launch required an authorization code supplied by the president and the turning of two keys by two highly disciplined human beings. So while Trinity could cause massive loss of life, it could not begin a nuclear war.

The president was not sure enough about Trinity's retaliatory limits to risk disaster. Five minutes before the deadline passed, he voluntarily put himself under surveillance. He first had several conversations with Ewan McCaskell, during which he outlined a stalling strategy of trading obedience for information from the computer. He also ordered that any action that could cripple the computer without risking massive loss of life should be tried.

Authority for this order was problematic. As soon as he was put under duress, the president would become legally incompetent to perform his duties. With the officials immediately in line for succession also compromised, a unique situation had arisen. No one felt comfortable turning over the Trinity crisis to the secretary of agriculture, who would become the chief executive from that moment forward. The members of Congress were scattered across the capital, and trying to assemble them without Trinity's knowledge would be impossible. To remedy this leadership vacuum, the president empowered a crisis management team to make all decisions regarding Trinity.

The team was composed of Ewan McCaskell, General Bauer, and as many members of the Senate Select Committee on Intelligence as could be hastily gathered in secret. A majority vote would carry all decisions. The senators convened at NSA headquarters at Fort Meade, where a video link protected by the agency's most advanced encryption system would allow secure communication with the White Sands Situation Room. A wide-angle shot displayed on the Situation Room's main screen showed the senators seated around a long table in a windowless room that looked like a bomb shelter.

Senator Barrett Jackson, the intelligence committee chairman, looked down from the video screen and said, "I can see them. Can they see us?"

"We see you, Senator. I'm John Skow of the NSA."

Senator Jackson was a bulldog of a man, with heavy jowls and deep-set eyes. A native Tennessean, he spoke with a drawl that belied his incisive intellect.

"I recognize General Bauer," he said. "Well ... all right. I've got a question for you experts. Why has this computer stopped communicating with us? Why isn't it saying more or demanding something?"

"It's consolidating its strength," said General Bauer. "That's the logical move. Godin's technicians are probably still loading data into its memory."

Skow nodded. "I concur. Both the NSA and CERN say Trinity hasn't let up on its tour through the world's computer systems. It could be absorbing literally every bit of that information as it goes."

"I see," said Senator Jackson. "General, paint me a picture of the worst-case scenario. What can this machine do to us?"

"Excuse me, General Bauer," Skow interrupted. "Before you do that, I feel duty-bound to at least mention the possibility of a Russian 'dead-hand' system."

"What the hell is that?" Jackson asked. "Dead hand? I seem to remember that phrase."

"You have a good memory, Senator," said Skow. "During the Cold War, Soviet planners knew that American strategy involved taking out their command and control systems with our first missiles. It was rumored that because of this, the Soviets developed what they called a 'dead-hand' system: a computer system that would automatically launch ICBMs upon receiving a missile warning by their coastal radar systems. Even if the Soviet leadership were killed, their 'dead hands' could still press the nuclear button. Rumors about this system originated in the U.S.S.R., but whether it was real or not has never been established. Later generations of Russian leadership denied its existence, and recent events have borne out this denial."

"Are you talking about the Norwegian incident?" asked a woman sitting at the back of the committee table.

Skow nodded. "Exactly, Senator. For those who don't know, in 1995, a Norwegian test rocket using the first stage from an American Honest John missile triggered a full nuclear alert in Russia, from the Strategic Rocket Forces up to Yeltsin himself. However, no retaliatory launch was made."

"So, does this 'dead-hand' system exist or not?" asked Senator Jackson.

"No, sir," asserted General Bauer. "During the Norwegian incident, the Russian command-and-control system functioned as it was designed to."

"Then what's Trinity talking about when it threatens to destroy the country?"

General Bauer could not hide his exasperation: "Senator, Trinity could throw our economy into chaos in a matter of minutes. If it attacked the currency markets, by Monday morning on Wall Street we could have panic selling unlike anything seen since 1929. Suppose Trinity attacks the trucking system? In three days, there would be no food on the supermarket shelves. We could have civil unrest within seventy-two hours, and widespread revolt within a week."

Senator Jackson sat back heavily in his chair. "Jesus Christ."

A soldier walked up to the general and whispered in his ear. Bauer looked up at the screen. "I've just received word that David Tennant and Rachel Weiss are about to arrive at the entrance of this base. They're in a helicopter, and they're going to land in the middle of that media circus."

Skow cursed under his breath.

"Tennant?" said a senator from the screen. "Isn't that the nut who was trying to kill the president?"

"He's the doctor who went public with the Trinity story," said Senator Jackson. "He used to be one of my constituents. I want him brought to your Situation Room."

"I agree," said Ewan McCaskell. "Dr. Tennant may have critical information for us."

Skow stood and faced the screen. "Senators, I've worked closely with Dr. Tennant for two years. He has severe psychological problems, including paranoid hallucinations. He's killed two men that we know of, and he's threatened the president's life."

"I've yet to see clear evidence of that last assertion," said McCaskell. "And Dr. Tennant's e-mail told a quite a different story."

"He's still dangerous," said Skow.

"Not surrounded by a squad of Special Forces troops," said General Bauer. "I'll send an escort for him."

"One of my Secret Service agents will go along," said McCaskell. "Just to be sure he arrives safely."

CHAPTER 40.

WHITE SANDS.

I clung to my seat as the chopper hurtled down toward a throng of people and vehicles outside the gate of White Sands. Inside the gate sat two humvees with .50-caliber machine guns mounted in back, their gunners standing at the ready. Rachel pointed at the swirling mass. It seemed to be made up primarily of journalists, but a group of demonstrators carried picket signs and crucifixes by the gate. They reminded me of the crowds in the Via Dolorosa.

I gazed north through the Huey's open door. Fifty miles across this desert, my father witnessed the detonation of the first atomic bomb. It was called, ironically enough, the Trinity Shot. He watched it from a bunker where high-speed cameras recorded every millisecond of the birth of the new sun. Many who witnessed that event tried to explain it, but none captured the moment the way Robert Oppenheimer did. I'd tacked his words on the wall of my medical ethics classroom at UVA: When it went off in the New Mexico dawn, that first atomic bomb, we thought of Alfred Nobel and his vain hope that dynamite would put an end to wars. We thought of the legend of Prometheus, of that deep sense of guilt in man's new powers, that reflects his recognition of evil, and his long knowledge of it. We knew that it was a new world, but even more we knew that novelty itself was a very old thing in human life, that all our ways are rooted in it.

As the Huey augered down toward the mob below, I realized that Oppenheimer had understood something Peter Godin did not. Godin had entered the Trinity computer to leave behind what no man had ever fully abandoned before: his humanity. In that quest, he could only fail.

The crowd surged toward the chopper as we landed on the far side of some TV trucks. We jumped out and tried to make for the gate, but someone recognized me and shouted my name, and that started a stampede. In seconds a storm of cameras, floodlights, and reporters was whirling around us. I stood still and silent until they quieted down.

"I'm David Tennant. I sent the note that revealed the existence of Trinity."

"What are you doing here?" shouted a reporter. "Aren't the people inside this fence the ones who were trying to kill you?"

"I think we're past that point now. But in case I'm wrong, you'll see me walk inside this base. If I don't come out again, don't stop asking questions until you get the truth."

"What is the truth?" asked a woman. "Is a computer holding the world hostage?"

"That's what I'm here to try to deal with."

"How?" shouted several voices at once.

A man with a French accent yelled, "Did this Trinity computer sabotage the Mohne River dam in Germany?"

"All I have to say is this. You're doing the world a service by remaining here. Whatever happens, don't leave. Thank you."

I tried to walk out of the circle, but the journalists refused to give way. Their shouted questions grew to a din, and they pressed in on us until the drumbeat of rotor blades drowned their voices. An olive drab Huey with miniguns mounted in its doors was settling almost directly overhead. When it dropped low enough, the reporters scattered like birds.

A young man wearing a business suit leapt from the Huey and ran toward me, shielding his face against the rotor blast. I saw a submachine gun beneath his flapping jacket.

"Are you Dr. Tennant?"

"Yes."

"I'm Special Agent Lewis of the Secret Service. Ewan McCaskell wants you to join him in the Situation Room on the base."

We ran to the Huey with the journalists flocking after us. As Rachel and I strapped ourselves into our seats, Agent Lewis scrambled inside and gave the pilot a thumbs-up.

Nose tilted forward, the Huey lifted over the high fence and beat its way westward. As the endless white dunes passed beneath us, I wondered that the newest form of life on the planet had been born in a waterless desert, as remote from Eden as one could imagine.

The pilot set down in the midst of several large airplane hangars. Our destination was a hangar marked ADMINISTRATION, and it was guarded by armed soldiers.

Inside the cavernous space we found a prefab command post that looked as if it had been designed by NASA. Seated around a table at its center were John Skow, Ravi Nara, Ewan McCaskell, and a two-star general I didn't recognize. A large display screen showed a group of men and women sitting at another table. Four I recognized as senators, among them Barrett Jackson, the senior senator from Tennessee.

On the far side of the table before me stood a hospital bed. Lying unconscious on it was Peter Godin. Beside the bed stood two nurses, a white-coated man who looked like an attending physician, and a blonde bodyguard wearing black. I was about to turn away when I saw a white bandage wrapped around the guard's neck. A gasp from behind me told me that Rachel had recognized Geli Bauer in the same moment I had. Geli looked at me, then past me, her eyes burning into Rachel. Her lips curved in a predatory smile. She had not forgotten Union Station.

Ewan McCaskell motioned us to chairs on the right side of the table and made quick introductions as we sat. I was surprised to hear that the blond general was named Bauer, but then I remembered Geli's family history. The people on the display screen were introduced as the Senate Select Committee on Intelligence, and it was clear to me that any decisions regarding the fate of Trinity-and thus the world-were going to be made by them.

"Dr. Tennant," said Senator Jackson from the screen. "We're glad you're here. In your e-mail from Israel you made serious allegations about Mr. Skow and the National Security Agency. I assure you that we'll look into those allegations at a later date. But for now, we have to focus on the Trinity threat."

"I'm here to do just that, Senator."

"We heard what you said to the reporters at the gate," said McCaskell. "Do you know of some way to shut down this computer without bringing down terrible retaliation on the country?"