incent Reynolds was walking down the chilly streets of SoHo, in the blue light of this deserted part of the neighborhood, east of Broadway, some blocks from the area's chic restaurants and boutiques. He was fifty feet behind his flower girl — Joanne, the woman who would soon be his.

His eyes were on her, and he felt a hunger, keen and electric, as intense as the one he'd felt the night he met Gerald Duncan for the first time, which had proved to be a very important moment for Vincent Reynolds.

After the Sally Anne incident — when Vincent got arrested because he lost control — he told himself that he'd have to be smarter. He'd wear a ski mask, he'd take the women from behind so they couldn't see him, he'd use a condom (which helped him slow down, anyway), he'd never hunt close to home, he'd vary the techniques and the neighborhoods of the attacks. He'd plan the rapes carefully and be prepared to walk away if there was a risk he'd get caught.

Well, that was his theory. But in the past year it'd been getting harder and harder to control the hunger. Impulse would take over and he'd see a woman by herself on the street and think, I have to have her. Now! I don't care if anybody sees me.

The hunger does that to you.

Two weeks earlier he'd been having a piece of chocolate cake and a Coke at a diner up the street from the office where he regularly temped. He glanced at the waitress, a new one. She had a round face and a slim figure, curls of golden hair. He noticed her tight blue blouse that was two buttons open and, in his soul, the hunger erupted.

She smiled at him as she brought his check and he decided he had to have her. Right away.

He heard her say to her boss she was going into the alley for a cigarette. Vincent paid and stepped outside. He walked to the alley and then glanced into it. There she was, in her coat, leaning against the wall, looking away from him. It was late — he preferred the 3 to 11 P.M. shift — and though there were some passersby on the sidewalk, the alley was completely empty. The air was cold, the cobblestones would be colder, but he didn't care; her body would keep him warm.

It was then that he heard a voice whisper in his ear, "Wait five minutes."

Vincent jumped and swiveled around to look at a man with a round face and lean body, in his fifties, with a calm way about him. He was gazing past Vincent into the alley.

"What?"

"Wait."

"Who're you?" Vincent wasn't afraid, exactly — he was two inches taller, fifty pounds heavier — but the odd look in the man's shockingly blue eyes spooked him.

"That doesn't matter. Pretend we're just friends, talking."

"Fuck that." Heart pounding, hands shaking, Vincent started to walk away.

"Wait," the man said softly once more. His voice was almost hypnotic.

The rapist waited.

A minute later he saw a door open in a building across the alley from the back of the restaurant. The waitress walked to the doorway and spoke to two men. One was in a suit, the other was in a police uniform.

"Jesus," Vincent whispered.

"It's a sting," the man said. "She's a cop. The owner's running numbers out of the restaurant, I think. They're setting him up."

Vincent recovered fast. "So? That doesn't matter to me."

"If you'd done what you had in mind you'd be in cuffs now. Or shot dead."

"Had in mind?" Vincent asked, trying to sound innocent. "I don't know what you're talking about."

The stranger only smiled, motioning Vincent up the street. "Do you live here?"

A pause then Vincent answered, "New Jersey."

"You work in the city?"

"Yeah."

"You know Manhattan well?"

"Pretty good."

The man nodded, looking Vincent up and down. He identified himself as Gerald Duncan and suggested they go someplace warm to talk. They walked three blocks to a diner and Duncan had coffee and Vincent had another piece of cake and a soda.

They talked about the weather, the city budget, downtown Manhattan at midnight.

Then Duncan said, "Just a thought, Vincent. If you're interested in a little work I could use somebody who isn't overly concerned with the law. And it might let you practice your... hobby." He nodded back in the direction of the alley.

"Collecting sitcoms from the seventies?" asked Clever Vincent.

Duncan smiled again and Vincent decided he liked the man.

"What do you want me to do?"

"I've only been to New York a few times. I need a man who knows the streets, the subways, traffic patterns, neighborhoods... who knows something about the way police work. The details, I'll save for later."

Hmm.

"What line are you in?" Vincent had asked.

"Businessman. We'll let it go at that."

Hmm.

Vincent told himself to leave. But he felt the lure of the man's comment — about practicing his hobby. Anything that might help him feed the hunger was worth considering, even if it was risky. They continued to talk for a half hour, sharing some information, withholding some. Duncan explained that his hobby was collecting antique watches, which he repaired himself. He'd even built a few from scratch.

As he'd finished his fourth dessert of the day Vincent asked, "How did you know she was a cop?"

Duncan seemed to debate for a moment. Then he said. "I've been checking out somebody at the diner. The man at the end of the counter. Remember him? He was in the dark suit."

Vincent nodded.

"I've been following him for the past month. I'm going to kill him."

Vincent smiled. "You're kidding."

"I don't really kid."

And Vincent had learned that was true. There was no Clever Gerald. Or Hungry Gerald. There was just one: Calm and Meticulous Gerald, who expressed his intention that night to kill the man in the diner — Walter somebody — in the same matter-of-fact way that he'd made good on that promise by cutting the son of a bitch's wrists and watching him struggle until he fell from a pier into the freezing brown water of the Hudson River.

The Watchmaker had gone on to tell Vincent that he was in town to kill other people too. Among them were some women. As long as Vincent was careful and didn't spend more than twenty or thirty minutes, he could have their bodies after they were dead — to do what he wished. In exchange, Vincent would help him — as a guide to the city and its roads and transportation system, and to stand guard and sometimes drive the getaway car.

"So. You interested?"

"I guess," Vincent said, though his private response was a lot more enthusiastic than that.

And Vincent was now hard at work on this job, following the third victim: Joanne Harper, their flower girl, Clever Vincent had dubbed her. He watched her take out a key and disappear through the service door to her workshop. He eased to a stop, ate a candy bar and leaned against a lamp pole, looking through the shop's grimy window.

His hand touched the bulge at his waistband, where the Buck knife rested. Staring at the vague form of Joanne, turning on lights, taking her coat off, moving around the workshop. She was alone.

Gripping the knife.

He wondered if she had freckles, he wondered what her perfume smelled like. He wondered if she whimpered when she was in pain. Did she —

But, no, he shouldn't think like this! He was here only to get information. He couldn't break the rules, couldn't disappoint Gerald Duncan. Vincent inhaled the painfully cold air. He should wait.

But then Joanne walked near the window. He got a good look at her. Oh, she's pretty...

Vincent's palms began to sweat. Of course, he could simply take her now and leave her tied up for Duncan to kill later. That would be something that a friend would understand. They'd both get what they wanted.

After all, sometimes you just can't wait.

The hunger does that to you...

Next time, pack warm. What were you thinking?

Riding in a pungent cab, thirty-something Kathryn Dance held her hands out in front of a backseat heater exhaling air that wasn't hot, wasn't even warm; at best, she decided, it was uncold. She rubbed together her fingers, tipped in dark red nails, and then gave her black-stockinged knees a chance at the air.

Dance came from a locale where the temperature was seventy-five, give or take, all year-round and you had to drive up Carmel Valley Road a long, long way to find enough sledding snow to keep your son and daughter happy. In her last-minute packing for the seminar here in New York, somehow she'd forgotten that the Northeast plus December equals the Himalayas.

She was reflecting: Here I can't drop the last five pounds of what I gained in Mexico last month (where she'd done nothing but sit in a smoky room, interrogating a suspected kidnapper). If I can't lose it, at least the extra weight ought to do its duty as insulation. Ain't fair... She pulled her thin coat more tightly around her.

Kathryn Dance was a special agent with the California Bureau of Investigation, based in Monterey. She was one of the nation's preeminent experts in interrogation and kinesics — the science of observing and analyzing the body language and verbal behavior of witnesses and suspects. She'd been in New York for the past three days presenting her kinesics seminar to local law enforcement agencies.

Kinesics is a rare specialty in police work, but to Kathryn Dance there was nothing like it. She was a people addict. They fascinated her, they electrified her. Confounded and challenged her too. These billions of odd creatures moving through the world, saying the strangest and most wonderful and terrible things... She felt what they felt, she feared what scared them, she got pleasure from their joy.

Dance had been a reporter after college: journalism, that profession tailor-made for the aimless with insatiable curiosities. She ended up on the crime beat and spent hours in courtrooms, observing lawyers and suspects and jurors. She realized something about herself: She could look at a witness, listen to his words and get an immediate sense of when he was telling the truth and when he wasn't. She could look at jurors and see when they were bored or lost or angry or shocked, when they believed the suspect, when they didn't. She could tell which lawyers were ill-suited to the bar and which were going to shine.

She could spot the cops whose whole heart was in their jobs and the ones who were only biding their time. (One of the former in particular caught her eye: a prematurely silver-haired FBI agent out of the San Jose field office, testifying with humor and panache in a gang trial she was covering. She finagled an exclusive interview with him after the guilty verdicts, and he finagled a date. Eight months later she and William Swenson were married.)

Eventually bored with the reporter's life, Kathryn Dance decided on a career change. Life turned crazy for a time as she juggled her roles as mother of two small children and wife and grad student, but she managed to graduate from UC-Santa Cruz with a joint master's in psych and communications. She opened a jury consulting business, advising attorneys which jurors to choose and which to avoid during voir dire jury selection. She was talented and made very good money. But six years ago, she decided to change course once again. With the help of a supportive, tireless husband and her mother and father, who lived in nearby Carmel, she headed back to school once more: the California State Bureau of Investigation training academy in Sacramento.

Kathryn Dance became a cop.

The CBI doesn't break out kinesics as a specialty so Dance was technically just another investigative agent, working homicides, kidnappings, narcotics, terrorism and the like. Still, in law enforcement, talents are spotted early and news of her talent quickly spread. She found herself the resident expert in interview and interrogation (fine with her, since it gave her some bargaining power to trade off undercover and forensic work, which she had little interest in).

She now glanced at her watch, wondering how long this volunteer mission would take. Her flight wasn't until the afternoon but she'd have to give herself plenty of time to get to JFK; traffic in the city was horrendous, even worse than the 101 Freeway around San Jose. She couldn't miss the plane. She was eager to get back to her children, and — funny about caseloads — the files on your desk never seem to disappear when you're out of the office; they only multiply.

The cab squealed to a stop.

Dance squinted out the window. "Is this the right address?"

"It's the one you gave me."

"It doesn't look like a police station."

He glanced up at the ornate building. "Sure don't. That'll be six seventy-five."

Yes and no, Dance thought to herself.

It was a police station and yet it wasn't.

Lon Sellitto greeted her in the front hallway. The detective had taken her course in kinesics the day before at One Police Plaza and had just called, asking if she could come by now to give them a hand on a multiple homicide. When he'd telephoned he'd given her the address and she'd assumed it was a precinct house. It happened to be filled with nearly as much forensic equipment as the lab at the Monterey CBI headquarters but was, nonetheless, a private home.

And it was owned by Lincoln Rhyme, no less.

Another fact Sellitto had neglected to mention.

Dance had heard of Rhyme, of course — many law enforcers knew of the brilliant quadriplegic forensic detective — but wasn't aware of the details of his life or his role in the NYPD. The fact he was disabled soon failed to register; unless she was studying body language intentionally, Kathryn Dance tended to pay most attention to people's eyes. Besides, one of her colleagues in the CBI was a paraplegic and she was accustomed to people in wheelchairs.

Sellitto now introduced her to Rhyme and a tall, intense police detective named Amelia Sachs. Dance noted at once that they were more than professional partners. No great kinesic deductions were necessary to make this connection; when she walked in, Sachs had her fingers entwined with Rhyme's and was whispering something to him with a smile.

Sachs greeted her warmly and Sellitto introduced her to several other officers.

Dance was aware of a tinny sound coming from over her shoulder — ear-buds dangling behind her. She laughed and shut off her iPod, which she carried with her like a life-support system.

Sellitto and Sachs told her about the homicide case they needed some help on — a case that Rhyme seemed to be in charge of, though he was a civilian.

Rhyme didn't participate much in the discussion. His eyes continually returned to a large whiteboard, on which were notations of the evidence. The other officers were giving her details of the case, though she couldn't help but observe Rhyme — the way he squinted at the board, would mutter something under his breath and shake his head, as if chastising himself for missing something. Occasionally his eyes would close. Once or twice he offered a comment about the case but he largely ignored Dance.

She was amused. The agent was used to skepticism. Most often it arose because she simply didn't look like a typical cop, this five-foot-five woman with dark blond hair worn usually, as now, in a tight French braid, light purple lipstick, iPod earbuds dangling, the gold and abalone jewelry her mother had made, not to mention her passion — quirky shoes (chasing perps didn't usually figure in Dance's daily life as a cop).

Now, though, she suspected she understood Lincoln Rhyme's lack of interest. Like many forensic scientists, he wouldn't put much stock in kinesics and interviewing. He'd probably voted against calling her.

As for Dance herself, well, she recognized the value of physical evidence, but it had no appeal to her. It was the human side of crime and crime solving that made her own heart race.

Kinesics versus forensics...

Fair enough, Detective Rhyme.

While the handsome, sardonic and impatient criminalist continued to gaze at the evidence charts, Dance absorbed the details of the case, which was a strange one. The murders by the self-anointed Watchmaker were horrific, sure, but Dance wasn't shocked. She'd worked cases that were just as gruesome. And, after all, she lived in California, where Charles Manson had set the standard for evil.

Another detective from the NYPD, Dennis Baker, now told her specifically what they needed. They'd found a witness who might have some helpful information but he wasn't forthcoming with details.

"He claims he didn't see anything," Sachs added. "But I have a feeling he did."

Dance was disappointed that it wasn't a suspect but a witness she'd be interviewing. She preferred the challenge of confronting criminals, and the more deceitful the better. Still, interviewing witnesses took much less time than breaking suspects and she couldn't miss her flight.

"I'll see what I can do," she told them. She fished in her Coach purse and put on round glasses with pale pink frames.

Sachs gave her the details about Ari Cobb, the reluctant witness, laying out the chronology of the man's evening, as they'd been able to piece it together, and his behavior that morning.

Dance listened carefully as she sipped coffee that Rhyme's caregiver had poured for her and indulged in half a Danish.

When she'd gotten all the background Dance organized her thoughts. Then she said to them, "Okay, let me tell you what I've got in mind. First, a crash course. Lon heard this yesterday at the seminar but I'll let the rest of you know how I handle interviewing. Kinesics traditionally was studying somebody's physical behavior — body language — to understand their emotional state and whether they were being deceptive or not. Most people, including me, use the term now to mean all forms of communication — not just body language but spoken comments and written statements too.

"First, I'll take a baseline reading of the witness — see how he acts when he's answering things that we know are truthful — name, address, job, things like that. I'll note his gesturing, posture, word choice and the substance of what he says.

"Once I have the baseline I'll start asking questions and find out where he exhibits stress reactions. Which means he's either lying or has some important issues with the topic I'm asking him about. Up until then, what I've been doing is 'interviewing' him. Once I suspect he's lying, then the session will become an 'interrogation.' I start to whittle away at him, using a lot of different techniques, until we get to the truth."

"Perfect," said Baker. Although Rhyme was apparently in charge, Dennis Baker, Dance deduced, was from headquarters; he had the belabored look of a man on whose shoulders an investigation like this ultimately — and politically — rested.

"You have a map of the area we're talking about," Dance said. "I'd like to know the geography of the area involved. You can't be an effective interrogator without it. I like to say I need to know the subject's terrarium."

Lon Sellitto gave a fast laugh. Dance smiled in curiosity. He explained, "Lincoln says exactly the same about forensics. If you don't know the geography, you're working in a vacuum. Right, Linc?"

"Sorry?" the criminalist asked.

"Terrarium, you like that?"

"Ah." His polite smile was the equivalent of Dance's son saying, "Whatever."

Dance examined the map of lower Manhattan, memorizing the details of the crime scene and of Ari Cobb's afterwork schedule the previous day, as Sachs and a young patrol officer, named Pulaski, pointed them out.

Finally she felt comfortable with the facts. "Okay, let's get to work. Where is he?"

"A room across the hall."

"Bring him in."