Katherine had just picked up her visitor's badge at the Medic Research front desk when a receptionist approached her with a smile.

"Dr. Isles?" the woman asked. Katherine nodded. "This way, please."

They went to the eighth floor of the building. The company had set up an extensive breakfast buffet in a meeting room.

Servants set the tables and carried in silver trays. Espresso and cappuccino machines had been set up, along with champagne coolers with various bottles of champagne on ice.

In one corner, several men stood, each holding a cup of cappuccino, talking in hushed voices. From what Katherine picked up, it was on medical topics.

"Kate," a voice said. "Welcome." Katherine spun around. Aaron Wolfsen stood before her, looking at her through his black glasses. He reminded Katherine of a vulture with his thin neck sticking out of his shirt collar and rimmed glasses. And over corpses, he circled, after all. "Glad you could make it. Today we have something exceptional. Can I offer you a little snack and a coffee? We don't have the big breakfast until after work, but it doesn't hurt to have a snack beforehand."

Katherine helped herself to a coffee and a mini croissant. As she did so, she looked at a mobile refrigerator that had been wheeled into the room and contained fresh sushi. You would have thought you were in a five-star hotel.

"I'm doing something wrong," the psychiatrist said as she bit into the croissant. "You guys seem well taken care of in the pharmaceutical industry. In our break room, we only have dry donuts from the day before yesterday, which we also have to pay for. The only thing you guys are missing is live cooking."

"We do live surgery," Wolfsen replied, smiling wryly. "Surgeries in real-time. The only thing we don't do is broadcast on TV."

"And these events?" asked Katherine, looking around. "Are they happening more often at your place now?"

Wolfsen nodded slowly. "Yes. Our customers, hospitals, and surgeons, really appreciate being able to look at our new instruments on a live object, so to speak, or, better, on a dead object."

"So you have real cadavers?"

"Why, yes. Nothing replaces real human matter when it comes to healing humans. Sutures, artificial heart valves, osteosynthesis for bones, plates, nails, and surgical techniques work much better with human material. And you can practice with it much better, too."

"So what's on the agenda today?" wanted to know Katherine.

"New instruments," Wolfsen replied.

Katherine nodded with a smile. "Well, you've always been better than me at surgery," she said, "Remember that time with the pig's paws?"

"Oh yes, I'll never forget that."

In medical school, they had practiced suturing wounds. On pigs' paws because pig skin was the closest thing to human skin.

"That's why you became a surgeon," Katherine replied. "Neurosurgeon, even." After all, she didn't have to rub his face at Wolfsen losing his license. "While I became a shrink."

"On top of that, for the tough cases. For serial killers and similar sympathetic contemporaries." Wolfsen's eyes widened in mock fear. "Let's have a quiet chat over breakfast later. Now we're going to get serious. Come along, Kate."

Katherine finished her coffee and followed Wolfsen and the others down a long hallway lit by fluorescent lights.

After all the participants had donned blue surgical scrubs and sterile gloves, they entered the room. On an OR table lay a severed human arm, and a right arm, as the psychiatrist immediately noticed.

Wolfsen walked to the OR table, a scalpel in his right hand and something that looked like a large thin syringe. The new instrument in question and a medical assistant stood behind him.

"Ladies and gentlemen," Wolfsen began, "today we are going to show you what Medic Research has in store in terms of new surgical instruments for what is known as carpal tunnel syndrome. In this condition, the nerve of the wrist is pinched because we all sit in front of the computer in unnatural hand positions more and more and for longer and longer periods. I assume many of you are familiar with the syndrome, as it's a common disease that affects hundreds of thousands of people."

He raised the scalpel and made an incision across the wrist of the arm. "Now, what does this look like exactly?" he commented, supplying the answer right away by pointing to the open wound, the image projected by a camera onto a large screen on the wall. "This," he said, "is the retinaculum flexorum, the flexor tendon ligament. It holds the tendons that run between the elbow and the hand." He showed a cross-section of a wrist. "Here are the carpal bones; the said tendon ligament up here. In between, run nine different flexor tendons for the fingers and thumb, all in a confined space and under high tension. If this ligament didn't exist, the tendons would protrude every time you bend your wrist, much like a worn-out rubber band." He made another cut. "Now the fact is that this very ligament," he pointed the scalpel at the tendon ligament on the corpse's hand, "is too tight in many people because of office work and the constant typing on keyboards. Many desk workers sit with claw-like hand postures in front of the keyboard and mouse, which causes many to have their hand fall asleep. It usually starts at night. They wake up and feel pain or numbness in their fingers. Brachialgia paraesthetica nocturna is the name given to this nocturnal disorder."

Some of the doctors nodded.

"Which, again, is due to the tendon being too tight and putting pressure on the vessels and muscles." Wolfsen raised another object in the air. "To make these surgeries as easy as possible while providing the most benefit to our patients, we made these micro-invasive instruments." He held up the syringe-like device. "Previously, you had to make extensive cuts into the joint ligament or split it. Today, that's no longer necessary." He looked at his audience expectantly. "Now we pierce the ligament with these new cannulas and stretch it that way. This reduces the pressure on the tendon, and the discomfort decreases. And now you can try it out for yourselves." He smiled, now not just like a vulture, but like a diabolical vulture, Katherine thought. "Let's get to work."

xxx

New York

Sergeant John Brooks of the Homicide Unit sat on a park bench across the street from the NYPD, squinting at the rising sun. "Of all the fucking places to meet, do we have to meet here?" he said glumly.

Ted Williams, who had arrived in town that morning, seemed to be vitality personified despite the morning hours. He sat down next to the sergeant and frowned a little. "I'm about to give a talk around here, and it's easier than if I'd gone to the hotel first. You're welcome to attend, of course."

Brooks scratched his chin less enthusiastically, pursing his lips. "I don't know. What's your talk about?"

Williams raised his shoulders and pulled the corners of his mouth down. "Perp profiles and ritual killings," he replied."

"Well, this is going to be edifying." Brooks lit a cigarette and blew the smoke into the morning sky.

"And what case are you on right now?"

"I ... well." He preferred not to say anything about his current case because then Williams would want the whole thing right away as a case study for the FBI Academy, as Brooks knew all too well. Abortion parties were always a feast for the FBI. So he told of another case. "We've been following a gang for quite some time that breaks into homes, ties people up, and squeezes out of them where the valuables are. Then they torture their victims with soldering irons, pinchers, screwdrivers, and shoot them."

"Holy crap," Williams groaned.

"The problem is that every time they do the deed, the motherfuckers take off across the state line. As you know, these guys are pretty much safe once they get across the border. If they go from New York to Pennsylvania, Pennsylvania is in charge. If they flee to Canada, Canada is in charge. If they run Massachusetts, Massachusetts is in charge. Then they go on there and come back to us." He puffed smoke into the morning air. "And in every state, the border agents take the position that their jurisdiction stops at the border. So we're chasing the same scumbags repeatedly, and we can't do anything once they get half an ass-cheek across the border."

"What about the FBI? That's what we're in charge of."

"The FBI doesn't give a shit." Brooks gave his old friend a long, frowning look. "So, to the point. You think the Angel of Death has a copycat in Boston?"

"At present, it looks that way."

Brooks shook his head. "Man, what a shit time it was back then. There was a murder almost every week. Ten in all, wasn't there?"

Williams nodded slowly. "Ten that we know of."

"And after Nate's death and Baldwin's arrest, all of a sudden, it was over."

William nodded slowly. "That's right, from one day to the next. "Baldwin messed up all our analysis. We thought the Devil's Staircase would apply to him, too. You remember?"

"Devil's Staircase?"

"Devil's Staircase?" Brooks shook his head. "Don't know it. I didn't spend that much time with you FBI eggheads; that was more Nate. I was mostly at crime scenes, some dark, blood-soaked rooms."

"Once a murderer believes he should murder again," Williams began, "certain neurotransmitters are released in the brain."

"What if he's just committed a murder?" wanted Brooks to know.

"Immediately after a crime, no more neurotransmitters can be released. It's similar to what happens with people with epilepsy. In some cases, the patterns of when an epileptic seizure occurs and when a killer's nodes are even identical. In the interval between kills, the neurons make new neurotransmitters released after a certain time, so the killer kills again." Williams drew a diagram on a piece of paper. "On the x-axis, we have time, and on the y-axis, we have the cumulative number of murders. In the end, over time, the total number of murders increases. The graph then takes the form of a staircase, the Devil's Staircase."

Brooks took another drag from his cigarette. "We caught Baldwin, thank God," he said.

"What if he has an accomplice?" retorted Williams with a slight frown. "Someone just waiting to carry on his work at that moment? You almost had a heart attack after Nate was killed, and then your divorce came. You have a score to settle with that monster. You'll feel better if we take these monsters down."

"A lot of people would be better off if you're right about your theory, Ted," Brooks said with compressed lips and a deep frown.

"So off to goddamn Boston?"

"Yeah, fine by me."