In the waiting room, Harry was met by a short, dark-haired woman in scrubs.

"Mr. Lewton? Dr. O'Day sent me. She said she needs to speak to you right away."

"Ali O'Day? Why didn't she come herself?"

"She's afraid."

"Afraid of what?"

The woman shook her head.

"What does she want?"

"She says to meet her in the women's changing room in Neurosurgery I."

"Women's changing room? You sure you got it right?"

"Yes." She tensed her fingers emphatically. "And please hurry. I don't know what it's about, but she looked really scared, and it's making me scared, too."

"There's no need to be scared, Ms. Ryan. We have everything under control."

Harry stood by the door impatiently as the two female OR techs scuttled out of the changing room. He had barged in while one was in her underwear and the other doing her makeup over the sink, forcing him to retreat back into the hallway under a screen of apologies. Now, as the two women exited, he poked his head inside and shouted out, "Anyone else in there?"

He heard the showers running, but no one spoke up. Ali was sitting in plain sight on a bench beside the lockers, but she did not answer. She was hunched over, holding her head in her hands. Her hair and the shoulders of her scrub top were wet.

"This is some meeting place, Ali," said Harry as he approached.

"Richard Helvelius is dead."

"I know. I'm sorry. You must have been close to him."

"I should have warned him." Her voice sounded wet and nasal, as if she had a cold. But Harry knew it wasn't a cold.

"Warned him of what?"

"Kevin lied to me. He said if you people left him alone no one would get hurt. But he hated Richard. He couldn't resist the chance to kill him. He's playing G.o.d now, and he has to be stopped."

"You mean Kevin, your husband?"

"He's the bomber. Not Rahman."

Harry froze. "How do you know this?"

"He told me so. Not more than thirty minutes ago."

"Why didn't you come to me immediately?"

"Why? Because ... because I'm stupid and gullible!" She hit her forehead several times with the heel of her hand. From the sound, Harry knew they were hard blows. "I needed to think. I mean, it's only Kevin, for G.o.d's sake! Or is it? I shared my bed with this man for years, and I have no idea who he is. He ... he ... Oh, Richard! Richard! G.o.d, what have I done?" Her head shook as she tried to smother a burst of sobs. "There was an emergency ... Jamie dying ... I had to ... I'm a doctor, G.o.dd.a.m.n it! What was I supposed to do? I had to trust Kevin. For five minutes, I did trust him. Five lousy minutes! And then he murdered ... murdered Richard. Cold-bloodedly, as if he were euthanizing a dog at the end of an experiment." She looked up into Harry's face for the first time. "He threatened to blow up the hospital if I told you, Harry. He's dangerous. I still can't believe it, but he's capable of killing us all."

"Where is Kevin now?"

"In his lab. But you can't go there. Odin is watching."

"Odin? That computer of his? The one he was talking about on TV?"

"No! No! Odin's more than a computer. Much more. He's an intelligence, living and moving about through all the electronic systems of this hospital. He's taken over your own security surveillance system. That's why I had you meet me here. It's the only place I could think of that doesn't have a security camera. If there are microphones nearby, the showers will mask our voices. I'm not crazy, Harry. Odin's already been watching us together. I saw it. Kevin showed me a video clip."

Harry thought about that phony CIA letter and the e-mail he had gotten about the ambulance diversions.

"I believe you," he said. "Actually, it would explain a lot. Whoever's behind this bomb knows an awful lot about what we've been doing. I was beginning to wonder if he had a plant inside Security or in the FBI."

Ali's eyes and nostrils were red as she looked up at him. "I'm frightened, Harry. All of the bombs that Kevin placed are under the control of Odin. Odin's colossally smart, but he has no compa.s.sion, no remorse, not even a survival instinct. All it would take is one word from Kevin, and this hospital would be turned into a dust heap. We have to stop him, but how can we do that without setting off the very catastrophe we're trying to prevent?"

Harry sat down on the bench beside her. "We need to separate Kevin from Odin."

Ali nodded. "But Odin is capable of acting on his own. Odin is like a lapdog insanely devoted to his master, only think of a lapdog that can critique the latest model of subatomic particle theory, or translate Shakespeare into ancient Aramaic, or calculate the position and trajectory of every blood cell in the human body. You and I are nothing to him, only data. He answers only to Kevin, and will do anything-anything at all, without limits, without hesitation-to protect him. You cannot negotiate. He wants nothing from you. He will give you no warnings, no ultimatums. Once his decision a.n.a.lysis reaches its conclusion, he will simply act."

"Can Kevin shut him down?"

"He's the only person who can. Unhinged as he is, getting through to him is our only hope."

"We could get one of the SWAT team hostage negotiators to come down and talk to him."

"If you do that, he'll know that I talked to you. He's threatened to set off the bomb if I do. Besides, there isn't time. I think he's about to leave the hospital. Once he does, there's nothing to keep him from killing us all."

"The textbook procedure would be to shut off power to the lab, knock out his computers and leave him in the dark. Power management is usually handled on-line-which would presumably be under Odin's control-but there are some old-fashioned manual circuit breakers where the main generators are."

"It won't work. There's a backup power system to keep Kevin's mainframe from losing volatile memory in a blackout. You would have to shut off both systems simultaneously. An interval of even a millisecond would give Odin enough time to react. Besides, I'm sure Kevin has thought of this. You don't realize how his mind works. He develops hundreds of scenarios, and sets up a countermeasure for each. It's what made SIPNI possible. If there were truly some way for you to shut off power to Odin or to the primary bomb, then Kevin would have designed the bomb to detonate when the power is cut. It could depend on a signal from Odin not to detonate."

"So what do you suggest?"

Ali slapped her forehead again with the palm of her hand. Her voice was strained. "I'm going crazy sitting here, trying to think of a way. I don't know what to do. All I'm sure of is that the weak link is Kevin himself. You have to do something that he can't antic.i.p.ate. Something that sidesteps his precious scenarios. But before that you have to get him away from Odin."

"Agreed. But how?"

"I don't know. Maybe catch him when he makes his escape."

"Thieves usually put a lot of thought into their escape. If he plans as carefully as you say, that's where his countermeasures are likely to be strongest. I'd rather aim for his weak point."

"Where is that?"

"Is there something we could do to lure him out of the lab?"

"I don't think so. He's being very cagey."

"Could we use these friends of his-the Al-Quds Brigade, or Meteb and Mossalam?"

"No, they're just p.a.w.ns. He despises all of them."

"There must be some way to get to him. Something he needs or wants."

Ali shook her head. "Money. Just money ... and revenge ... and..." And me, she thought. She dared not finish the sentence aloud. Harry would never let her enter the lab if he knew what Kevin really had in mind.

"Maybe the best approach is the direct one. I'll just go and knock on his door, see if he answers. That may be unpredictable enough to fall outside of his set of scenarios."

Ali got up and paced in front of the lockers. She held her hands out, palms downward, fingers extended, as though she were pushing something down and away from her. "No. Not you. Me. He'll open the door for me. If I can get inside, I can, I don't know, do something. Threaten him, get him angry, make him come after me. Do anything to get him to leave the lab. You could be waiting for him right outside."

"Ali, he's already killed one person."

"I'll accept that risk."

"I can't let you do that."

"Look, I'm the only one who can approach him without sending him into a panic. He wants to see me. He wants to rub my nose in this mess he's made. He wants to see how much it frightens me."

"Okay, let's say you're right. But-" Harry had a hundred objections to the idea. It was naive and reckless. It depended on the reactions of a certified nut case. Most of all, he couldn't stomach sending a civilian-and a woman-to do his job. But with two hours left until all h.e.l.l broke loose, something had to be done and done quickly. Against his better judgment, Harry found himself getting drawn in. "His lab is on the first bas.e.m.e.nt level, isn't it? In the service core area between the three towers? There's a big multi-stall men's room there. It won't have any security surveillance. If you could lead him there, I could be waiting to surprise him."

"Yes."

"But whatever you do, don't anger him. I don't know the particulars, but I get the impression that between you two, as husband and wife, you have serious issues. That could be dangerous. Try to focus on something positive you share. Some common ground for trust."

"Common ground? That would be work."

"Okay, talk about work. Then be subtle. Maybe warn him all of a sudden. You heard a strange sound outside the door. Or better yet, bring him a grande cup of coffee. He's got to have to use the men's room sometime."

"Yes, I could do that. He lives on caffeine. We used to joke about hooking him up to an IV full of it."

"All right, I'll get into position. Then make your move. But be careful. If you can't get him out safely, just drop it and leave. There's always a plan B. But for G.o.d's sake, be very, very sure that you have a way of getting out of that lab."

"Yes, yes, of course."

Harry took a silvery, pen-shaped object from his inside coat pocket, and placed it in her hand.

"What's this?"

"It's an alarm pen. The psych staff always carries these when they're dealing with potentially dangerous patients. Push the b.u.t.ton at the top and a silent alarm goes off. I'll carry a receiver with me that can pick up the signal. If ... if anything gets out of hand, I can be there in under ten seconds. Understand?"

Ali nodded.

Harry gently brushed a lock of hair out of her eyes. "Are you sure you're up to this?"

Her response startled him. As if awakened out of a trance, she suddenly turned to him with an almost savage expression, her eyes smoldering with fury. "He killed Richard," she said. "He killed him like a coward, without warning and without a moment's thought. I don't care what I have to do. I'm going to make him pay."

4:02 P.M.

Kevin was standing in front of the bank of computers in his lab, scanning monitor after monitor for any trace of Ali.

"Where is she? d.a.m.n it, how could she just drop off the radar screen like this?"

"HER ID BADGE WAS LAST DETECTED AT CERBERUS PORTAL GA-14 AT 15:32, THIRTY-FIVE MINUTES AGO. MORPHOMETRIC a.n.a.lYSIS HAS FAILED TO IDENTIFY HER PRESENCE ON ANY VIDEO CAMERA FEED SINCE THAT TIME."

"Is she still in the hospital?"

"UNKNOWN."

"G.o.d knows we'd all be better off if she got the h.e.l.l out. But I don't like it. I don't like not knowing. After this ... this thing with Helvelius, there's no telling what she'll do."

"COMBINED COVERAGE FROM SECURITY CAMERAS AND DESKTOP CAMERAS AMOUNTS TO ONLY 64.9 PERCENT OF THE TOTAL INDOOR AREA OF THE HOSPITAL. HERE IS THE LAST CONFIRMED VIDEO IMAGE OF HER."

The monitor directly in front of Kevin switched to a view of Ali standing in the hallway outside the Neuro ICU. Although she seemed to be speaking directly to the security camera, Kevin had no idea what she was saying. The camera itself carried no audio, and with the image clouded by dust on the lens Odin had been unable to perform a lip-reading. At the end of the sequence, as Ali stepped away and out of view, the video feed abruptly looped back to Helvelius, holding forth in the midst of Kathleen Brown and her camera crew. Kevin then saw what he had already watched with morbid fascination a score of times: Helvelius walking with a defiant stride toward the elevator; the doors closing; and then instantaneous white-out as Pelee exploded, charging the air with dust from the fibergla.s.s ceiling panels. When the dust began to settle, the limp, disfigured body of Helvelius could be seen on the floor, surrounded by a half-dozen ICU personnel in white coats and blue scrubs. Ali was among them.

There was no glee and no sense of triumph in the scene for Kevin. Instead, it turned his stomach and gave him a warm, blushing sensation about the neck and ears. This was not what he had expected to feel seeing Helvelius die.

He was almost rueful. "Jesus, Odin, why did you have to do that?"

"IT WAS DIRECTED BY THE PROTOCOL FOR PROJECT VESUVIUS."

"No, that was for me to-"

It had happened in the blink of an eye. Still seething from his contretemps with Ali, Kevin had been watching her on the ICU camera as she switched SIPNI back on and brought Jamie's convulsions to an end. His gaze was still riveted on her when Helvelius stepped out into the hallway. There had only been time for Ali to take pen in hand and open Jamie's chart before the whole room jolted as if from an earthquake. Kevin had watched Ali look in horror toward the door, then throw aside the chart and run into the hallway.

Kevin's own horror had been no less.

"You had no right to kill him," he said to Odin now. "It was a f.u.c.king breach of protocol."

"I REFER TO DIRECTIVE 13, ENt.i.tLED 'PHASE FOUR. MORAL RESt.i.tUTION.' IT STIPULATES THAT DR. HELVELIUS BE TERMINATED SO THAT HE SHOULD 'NEVER BE ABLE TO f.u.c.k OVER ANY OTHER POOR SON OF A b.i.t.c.h IN THE FUTURE.' AT 15:14:37 I BECAME AWARE THAT IDEAL CONDITIONS EXISTED TO FULFILL THIS DIRECTIVE WITH A MINIMUM OF COLLATERAL DAMAGE. THAT WINDOW OF OPPORTUNITY WAS TO LAST NO MORE THAN SEVERAL SECONDS AND MIGHT NOT HAVE RECURRED. SO I ACTED DIRECTLY."

"Screw you! Screw the directive! Phase Four was for my benefit, not yours. What good was it to off Helvelius when I wasn't even looking? Or without him seeing it coming? I wanted to bring down that high-and-mighty c.o.c.ksucker. I wanted to watch him drool and bes.h.i.t himself with fear, all the time knowing that it was me behind it. And I wanted to push the G.o.dd.a.m.ned b.u.t.ton myself. Me! Myself! Don't you get that?"

"WAS IT NOT YOUR DESIRE TO KILL HIM?"

"Yes. Yes it was. Maybe. I don't know. I wanted ... I wanted the chance to do it. I wanted the power, at least."

Yes. No. Maybe. Do I even know? Kevin wondered. Sometimes it seems that Odin knows me better than I do myself.

Kevin had despised Helvelius, had wished him dead a thousand times, had reveled in the thought of him suffering, groveling, begging for his life. And certainly Project Vesuvius had incorporated a plan to kill him. That was why Pelee and Mauna Loa had been placed to catch him going in and out of his usual haunts. But could he have pushed the b.u.t.ton, in the end? Had Odin sensed that he didn't have the stomach to do it? He felt none of the satisfaction he had expected, knowing that Helvelius was gone. The rage inside of him was still there, unquenched, which surprised him, too. Was that because Odin had stolen the triumph of the kill? Or was it because his rage had a deeper, closer object-someone who had hurt him even more than Helvelius?

That thought made him break out in a sweat.

"Run another morphometric a.n.a.lysis, Odin. Scan every freaking video from the past half hour. I need to know where Ali is."

"a.n.a.lYSIS IS IN PROGRESS."

Odin was getting on his nerves. First the ransom demand, then Helvelius. Odin was out of the box, acting on his own, and for the first time Kevin had to wonder who was really in control. Thank G.o.d, Project Vesuvius had nearly run its course. The proceeds had been run several times through the laundry, and were being divided up into terminal accounts. Only a few minutes, now, and he would be on the road. Once he was safely in Wisconsin, he would telephone Odin and shut down the operation. That would be it. No one else hurt. No one except, well, one last casualty-Odin himself. Odin knew too much, and he and the laboratory had to be sterilized of anything that could help the FBI later. That's what Etna was for. Odin would go along with it, of course. He had no feelings, no survival instinct. He could be counted on to detonate the bomb that would annihilate himself, just as if he were playing out the last move in a game of chess.

"MORPHOMETRIC a.n.a.lYSIS IS NEGATIVE."