11:21 A.M. PST.

In the back of her ex-husband's Jeep, Katrina felt almost airborne as the Jeep flew eastbound on the 8 freeway at more than one hundred miles per hour. She had no idea if there would be highway patrol after them, and she didn't care. Her only concern was getting Alexis to the lab.

Sean McMullan broke a long silence abruptly. "Where in the h.e.l.l does Guofu Wong get off being our killer?" he shouted. "All this time, I was sure it was Johnson."

Katrina looked at him. "Wong framed Johnson," she said. "He convinced you that I had plagiarized his data. That's why you thought it was him all along."

McMullan paused for a moment, and then mused, "Wong certainly had the resources to orchestrate the attack at the prison. But there's no way he worked alone. He had an accomplice." He turned to Katrina. "It had to have been someone from your lab who started this whole thing. I still can't imagine why."

"We were a.s.suming he was going to poison the scientists at the convention," Katrina pointed out. "But Wong was going after the protestors. It does make sense. You told me Wong wanted to fund my initial grant application a year ago because he was so in favor of biotechnology. He worked for the CDC and within the NIH. He knew how under-funded this type of research is. He knew how vulnerable to a biological attack our country really is, and how little is being done to promote the research that can stop one."

The Jeep approached the exchange for the 15 freeway, and a highway patrol car parked along the shoulder came into view. Tom quickly hit the brake to reduce his speed and then pa.s.sed the officer, glancing into his rearview mirror. The highway patrolman did not follow.

"That's right," McMullan said. "In the greeting card, he wrote, 'when I have been martyred for a cause you can never appreciate any other way.' Wong considered himself some kind of warrior for science. And a long time ago, he told Gilman that the word conscience means literally 'with science.' He must have thought he was really doing the right thing-making a necessary sacrifice for the greater good."

"Something a jarhead can relate to," Tom chimed in.

"Me too," Katrina agreed. "Despite what Lexi thinks, I always felt that way about animal research."

Alexis had been staring through the window. Katrina had thought that she was not listening to the conversation, but when her name was mentioned, Lexi spoke up. "He said something else, too," Lexi said weakly. "He said to me, 'These fools down here, they're just ignorant. They'll get the cure and they'll learn. But you should have known better.'" Looking pained, Alexis turned her head slowly to look at her mother sitting behind her. "He was counting on you to save the other protestor's lives," she said weakly, "but not mine."

Katrina looked at her daughter and understood Wong's strategy. The others had ingested the bacterium. Their illnesses would be slower to manifest. But Alexis had been injected. The distribution through her body had been immediate. Alexis had much less time.

11:26 A.M. PST.

In 1954, Jonas Salk changed summertime forever.

Prior to the release of Salk's vaccine for poliovirus, parents of young children spent the season in a state of panic. Would their children come down with the crippling disease while they stood helplessly by, or would they escape it for another season?

As the vaccine became commonplace, the nation reveled in relief, and the summer season once again became a time of enjoyment for children and parents alike. Polio was all but eradicated.

A common myth is that Salk injected one of his children with the vaccine in order to prove its efficacy and safety to the public. The truth, however, is that he injected all three of his children. And his wife, his laboratory staff, and himself.

As Katrina opened the freezer in her laboratory s.p.a.ce at San Diego State University, she was wishing for Jonas Salk's confidence. Despite the a.s.surance she had offered McMullan at the jail just the previous day, and despite the fact that she had already stockpiled the formulation, Katrina was terrified.

The antidote had been developed way too quickly. There had been no time for proper trials-not even in primates. There was no way to know the drug's effectiveness, and there was certainly no way to know its long-term safety. The first human subject to test the antidote for the Death Row anthrax strain would be Katrina's only daughter. The only child she had left. Alexis would be the guinea pig.

Katrina reached into the freezer and pulled out a box, from which she removed a small gla.s.s vial. As if in a trance, she stepped away from the freezer, leaving the door open behind her. Ice-cold sublimation billowed outward.

Tom exchanged a glance with Sean McMullan, who wordlessly stepped to the freezer and closed the door.

Katrina walked to the cold room as if to a gallows. Once inside, she rummaged mindlessly through a shelf until she found an unopened bottle of solvent. She tore the protective wrapper from its cap and dropped it to the floor as she left the cold room. Again, the door left open. Again, McMullan behind her to close it.

Alexis was sitting on a lab bench with her head in her hand. She was shivering.

As she approached her daughter, Katrina reached into a cabinet and found a sterile needle and syringe, which she unwrapped and connected while walking. Standing in front of Alexis, Katrina brushed the condensation from the sides of the gla.s.s vial. It had finally begun to thaw.

For what seemed like hours, she rubbed the gla.s.s vial between her trembling hands to thaw its contents completely. Then she filled the needle. Her hand was cold as she reached for her daughter's arm.

Katrina brought the needle forward, but could not still the shaking of her own hands sufficiently to administer the injection. Her breathing shallow, she closed her eyes and swallowed hard, then stepped backward. A tear rolled down her cheek.

Tom reached forth and took the needle gently from his ex-wife. "IV or IM?" he asked softly.

Katrina's response was barely audible. "IV."

Tom turned Alexis' arm to reveal the soft inner flesh. He tapped the skin in the crook of her elbow to locate the vein. Tom's eyes met Lexi's and held for a moment as he took a deep breath and let it out slowly. After a final glance at Katrina, with the expert precision of an experienced combat medic, he pressed the needle into Lexi's vein as lovingly as possible and depressed the plunger.

Katrina could not look away.

A few moments later, the silence was broken by Sean McMullan. "We have to... " His voice cracked slightly, and he cleared his throat and began again. "We have to get you to the hospital," he said. "And I'll get a courier from the FBI to transport the rest of the antidote there, too."

As the three others began slowly guiding the weakened girl toward the door, Alexis shook her head gently. Then she reached over and laid an arm onto Katrina's as if to detain her. Katrina stopped walking and turned to face her, leaning in close to hear the feeble voice. "Go get the b.a.s.t.a.r.d who did this to me," Alexis whispered.

Katrina looked into her eyes, and then toward McMullan, and then Tom.

"I'll take her," Tom said. He put his arm around Lexi and scooped her up into his arms for the third time that day, then carried her out of the lab.

When McMullan turned back around, Katrina was gone.

11:28 A.M. PST.

Katrina wandered through the empty office s.p.a.ces adjacent to the lab, not knowing what she was looking for. In the absence of Tom and Christopher, her staff members had become like her family. She could not believe, could not imagine that any of them would have done this. But McMullan was right, and Gilman had been right all along. It had to have started here.

Guofu Wong's dying words rang through her mind once again. It was your activator. It was indeed.

Katrina walked into the office shared by Li, Oxana, and Jason and scanned the tall bookshelves and works.p.a.ces. Each of the desks was piled with its own stacks of loose journal papers. She walked over to Li's.

Li was the most organized person Katrina had ever known. The three-ring binders and lab notebooks on her bookshelf were clearly labeled and ordered, first by function and then by date. Except for one small picture of her husband and infant daughter in Beijing, Li's desk was devoid of personal effects. Katrina pulled Li's most recent notebook from the shelf and thumbed through. All of her data was scanned, her notes typed. Each experiment was clearly catalogued in a table of contents and detailed according to cla.s.sic scientific method: objective, materials and methods, results, and conclusions.

No way, Katrina thought. This is the most well-behaved girl on the planet. She slid the notebook back into its slot and looked over at Jason's desk.

In sharp contrast to Li's meticulous style, Jason was, and had always been, a total pig. Katrina had never complained, as Jason's work itself was meticulous and he had always been an exceptionally prolific young scientist. Everyone seemed to agree that his promise was endless. His eccentricity reminded Katrina of Richard Hoffman, the chairman of biology at SDSU. Or Einstein.

In addition to the haphazard collection of unlabeled notebooks and creased, well-worn journals, Jason's bookshelf held CDs, empty liquor bottles, and dirty coffee cups. The wall above his desk was plastered with photos, mostly of large, rambunctious parties. A computer printout on the left wall next to his chair showed a smiling man holding a steaming beverage cup. The caption beneath read "How about a nice warm gla.s.s of shut the f.u.c.k up?"

Katrina pulled a notebook down from the shelf. A stack of loose paper, films, printer paper, and bar napkins with notes scrawled in Jason's barely legible writing fell out. Katrina flipped through some of the data, decided nothing looked out of the ordinary, and quickly gave up trying to decipher his madness. She stuffed the wad of information back into the binder and returned it to its spot.

As she shoved it between two other books on the shelf, an item fell onto the desk below. Jason's CD. She had seen it before. She had even been to a couple of Jason's shows over the years in the spirit of support, although she could not stand heavy metal.

The front of the CD case showed a topless, blindfolded woman. Her arms were raised and stretched as though she were being crucified. The alb.u.m was self-t.i.tled, and the name "Lethal Factor" was displayed over the woman's bare b.r.e.a.s.t.s. Two years earlier, Katrina had laughed when Jason told her that he named his fledgling band after his work.

She picked up the CD to return it to its shelf, but then paused as a line of text on the back of the square case caught her eye. She looked again, and her breath caught in her chest.

Track Seven was ent.i.tled, "Message From a Terrorist," and in smaller lettering beneath, subt.i.tled, "Dear Mr. President." Katrina quickly recalled the translation of the terrorist threat from the original greeting card, the one received at the White House all those lifetimes ago. It had begun exactly that way.

Katrina focused on her breathing to stay calm as she carried the CD out into the lab. With slightly trembling fingers, she turned on Jason's CD player and put in the CD, then skipped to Track Seven.

Distorted guitars and drums began their frenzied crashing at once. Katrina waited for the vocals to come in, trying to convince herself that she was just being paranoid, that the stress had finally gotten to her. Then the lyrics began, and she realized she could not have been more wrong.

Dear Mr. President, Your nation of puppets will soon know at last the price of fighting against our Islamic State. Those of you who survive Allah's justice will reflect upon 11 September of 2001 and consider that date insignificant...

It was the message from the card. Verbatim. Blinking back frustrated, incredulous tears, Katrina started the track over again, struggling to make out the screaming vocals over the overbearing guitars. She could only catch some of it.

She clawed open the CD case and pulled out the sleeve, unfolding it into its eight panels. The sleeve contained acknowledgements from the band collectively and from each band member individually, production studio and artwork information, equipment, and copyright information. She flipped the sleeve over to look for the song lyrics.

Katrina's eyes were instantly drawn to the Track Seven lyrics. They were written in Arabic script.

The CD was still playing when Katrina realized that Sean McMullan was standing right next to her. He was looking over her shoulder at the Arabic text. The cacophony had become a soundtrack for a h.e.l.l Katrina could no longer even understand.

McMullan seemed to realize this, and he sounded almost sorry when he said, "I think I have some questions for your postdoc, Katrina."

"So do I." She looked at her watch. "He's at the convention."

"Oh, great," McMullan said. "The hardest place I can think of to get to him, find him, and pick him up without a problem."

Katrina sighed. "At this point, we won't even be able to get in until the day's sessions are almost over. Jason could already be gone anyway. We could get down there and run around looking for someone who has already gone home."

"Then we go to his apartment and wait for him there."

"OK," Katrina said, "except that we don't have a car. Yours is at the convention center and mine... in the parking lot at San Quentin, I think. I don't remember. But neither of our cars is at SDSU and we are. Call Gilman."

McMullan looked down and sighed. "I can't," he said. "I didn't exactly tell him that I was pulling you out of jail. We're on our own."

Both Katrina and McMullan fell silent, each of them engrossed in the latest roadblock. At first, neither noticed when the door to the lab quietly opened and closed. But then, someone laughed.

Katrina foggily looked up to see Josh Attle.

"You guys closet Lethal Factor fans?" Josh asked cheerily.

Katrina reached forward and turned off the CD. The silence was golden.

"I feel a little awkward saying this," Josh said, "but I thought you were in jail?" His face was clouded with concern, and Katrina sighed.

"Yeah, I got out," she said, without offering more.

"Good," he said. "I never doubted those guys were whacked for thinking you could have done anything wrong." Josh winked at Katrina.

She offered what she hoped to be a sincere smile and turned back to McMullan. As she did, Josh nodded and stepped past them toward his lab bench.

"We need your car," McMullan said abruptly.

Josh turned back around. "Huh?"

Katrina looked at McMullan and then at Josh. "I can't explain it," she said, "but soon enough, I promise you'll know what's going on. Please?" The "please" was a gesture. Katrina knew that McMullan could merely take the car, but she had no reason to cause problems with Josh. Or to believe that he would say no.

"I wasn't planning on being at the lab for very long," Josh protested. "I was planning on just doing something quick here and then going home. I'd rather not end up stranded."

"Take a taxi," McMullan said. "It's on the FBI. Where are your keys?" Josh reached into his pocket and produced them. McMullan took the keys and then reached forward to pop the CD out of the player. He returned the disc to its case and dropped the case into his own pocket.

11:37 A.M. PST.

Behind the wheel of Josh's decrepit car, Katrina sped inland toward Santee.

McMullan was staring blindly out the window. "I don't think anyone else heard," he finally said.

Katrina looked at him, not understanding. "Heard what?"

"I was right next to you when Wong died," McMullan said. "I heard what he said to you. That it was your activator. But he was barely whispering, and I think the press was too far away to catch it."

Katrina wondered where he was going with this. "Yeah?"

McMullan's eyes bored into her for a moment. "That's good, Katrina," he said. "If the press heard that, you're screwed. If they didn't hear, then maybe we can still contain this. Provided, of course, that we get to Jason and clear the rest of it up for good."

Katrina had not even been thinking about the ramifications of Jason's involvement with respect to her, but now, she gave McMullan a grateful look and then sighed. "Yeah, I guess you're right," she said.

The struggling motor of Josh's car protested when Katrina asked for a burst of speed to pa.s.s another car. As she approached the rural town of Santee, the ratio of full-sized trucks to pa.s.senger cars increased dramatically.