"You're particularly chic today," Nikki greeted her mother with a grin at a police tape. "Is there a special reason?"

She and her sister Ashlyn hadn't been shocked when their parents announced their separation; the two young women had more or less been able to watch their parents' relationship go from bad to worse.

Nikki was an athletic woman, a little tomboyish, but never unfeminine. She usually wore her brown, shoulder-length hair in a ponytail when on duty, and her alert, light blue eyes were as unobtrusive as the rest of her striking face.

Elizabeth rolled her eyes as she ducked under the barrier tape. "What would you assume?"

"You had a date," Nikki concluded with an expression of joy that quickly gave way to remorse. "Don't tell me I ruined it for you."

Elizabeth looked at her daughter seriously. "Quite the opposite. You saved me!"

The younger woman was disappointed. "Nothing again? How many times has that been since Mom and you broke up?"

Elizabeth took a deep breath and gritted her teeth. "The fifth. She was beautiful but stingy. You don't have fun with stingy women."

This time, it was Nikki who rolled her eyes. "So this time, it was stinginess. I suppose she gave herself away with something again?"

"She had a fake Prada handbag."

Nikki chuckled. "She told you her handbag was fake?"

"The stitching told me. Poorly made. That would never happen with an original. She also read the menu from right to left. First the prices, then the dish." Elizabeth grinned with suppressed pride as she added. "I told her the story about the Frenchman and the rats. I don't think she'll want to date me again."

"You didn't," Nikki followed up as Elizabeth turned her attention to the body under the tarpaulin.

Instead of going any further into their failed date. Elizabeth looked at her daughter briefly. "Who do we have here?"

The house from which the victim had fallen to his death had eight floors, was located away from the hustle and bustle of the city in a quiet outlying area, and was easily accessible at any time of day. It seemed to have been perfectly suited to the killer's plans.

"This is Rick Frye, an old acquaintance," began Nikki, who had already had the dead man's identity checked. "He's a real estate agent with a pretty big company."

"A real estate agent," Elizabeth repeated. "Then it's not such a pity about him. Nobody needs them anyway. What do you mean, actually?"

"His colleagues call him the climbing monkey," the younger woman reported. "He climbed some tall buildings at least once a year. Unsecured, and of course, without permission. We last arrested him when he climbed a high-rise building near my neighborhood. That was last summer."

"Near your neighborhood," Elizabeth repeated, shaking her head. She took another deep breath of the cold air and finally lifted the tarp.

Frye had suffered multiple fractures to his ribs and vertebrae on impact. His lower leg was sticking out at an unnatural right angle at knee level, and the impact on the back of his head had caused a large amount of blood and brain matter to spill out, but it had frozen to the ground.

Elizabeth let the tarpaulin sink dispassionately back onto the dead man. "He's wearing street shoes, has no gloves on, and this building is completely unspectacular and away from the public eye. He wasn't working as a cat burglar. At least not voluntarily."

Nikki shifted her weight from one foot to the other and licked her lips. "We could have been here sooner, but the uniforms thought it was a suicide at first."

"He's on his back," Elizabeth replied. "How many suicides jump backward to their death?"

Nikki pressed her lips together and, nodding, handed her mother an evidence bag containing a greeting card. "Here's the link to our current serial killer."

The card depicted a little boy holding colorful balloons. Underneath the picture was a big five. "Maybe he was going to a child's birthday party?" Elizabeth tested her daughter's theory.

Nikki shook her head with furrowed brows. "He has no children, nephews, nieces, or anyone else who will be five in the next few days. And no, not a fifth anniversary of anything either," she reported from her initial phone research. "Look at his hands."

Elizabeth now squatted carefully in front of the corpse, careful not to touch the pool of blood and ice with her pants, and lifted the tarp slightly once more.

When she took a closer look at the dead man's unnaturally cramped hands, she noticed that they were shiny. "Oil?"

"Both hands were smeared with it. Our killer wanted to ensure he didn't get to the top."

"To the bottom," Elizabeth corrected her daughter. "He didn't climb up; he climbed down." She stood up again and looked up at the building.

It was well suited for a cat burglar; the architecture offered plenty of opportunities to find a foothold on the steep front.

Elizabeth looked closer at the building and then pointed to the ledges a cat burglar would have used. "There are no traces of oil anywhere on the wall. I assume some are on the roof and the upper outer wall. We can use them to determine where he fell." She looked at the body again and realized: "He can't have fallen very far."

With a wave, she indicated to her forensic colleagues that they could now take the body away.

While they set about putting the body's leg back in place for transportation, Elizabeth asked her daughter: "Have you thought about the numbers our idiot colleagues have found?"

It was obvious that it still went against her grain that Daniela Castella had forbidden her to personally investigate the case when the serial killer's first victim had turned up and that Castella had gone over her head and assigned this particular case to two detectives who weren't really known for their clearance rates.

Elizabeth was pretty sure that the decision had to do with the fact that one of the detectives was related to a city councilman who wanted to see his son's name in the news in a positive sense.

Nikki snorted, equally annoyed. "Of course. We've got four dead now; the highest number so far was seven." She looked over at the body bag that was now being pushed into the coroner's van. With a worried look, she said, "We've got four, five, six and seven so far. If the killer is working off a fucking list, which we have to assume he is --"

As the hearse made its way to the morgue, Elizabeth finished her daughter's thought, "...then at least one, two and three await us."

xxx

"First, the key to everything is the numbers," Elizabeth opened the unofficial team meeting in a conference room. "They document the pattern of what he's doing. If we recognize this pattern, we might be able to get ahead of him." She looked around with a seriousness tinged with irony as she moved on to the next point. "Secondly, this killer doesn't have a nickname yet, which I find extremely impractical. Any suggestions?"

Chief of Police Daniela Castella stood in the doorway without warning, arms crossed in front of her chest.

Elizabeth looked over her shoulder and frowned deeply, realizing she and her team had been caught. With a wave, she invited the chief to join the meeting.

Castella took a deep breath and sat down next to Nikki, who inevitably clenched her teeth.

For days now, Elizabeth's handpicked team of investigators had been feverishly searching the victims' surroundings in secret, looking for usable clues, calendar entries, suspicious phone calls, or anything else that could provide a useful clue to the identity of the murderer.

However, it soon became apparent that the wanted man had not only acted with conspicuous attention to detail but also that there appeared to be no personal connection between him and his victims. The perpetrators' actions were meticulously planned, highly skilled, and extremely cautious, which made the investigators' work considerably more difficult.

"Count von Count?" suggested Nick.

"Too disrespectful," Elizabeth rebutted and continued without thinking. "All of us in this room are wondering what the killer is trying to say with his numbers. It could be points he's awarding his victim. Maybe the numbers in the right order make up a combination or a phone number. It could just as easily be something completely private, an inside story between the killer and the victims." She let her gaze wander around the room scrutinizingly. Her team followed her explanations attentively, which secretly flattered her vanity. "But none of that is an option. Why?"

"Because it's all too convoluted and unlikely," replied Mike Fisher, one of Elizabeth's handpicked team.

Elizabeth closed her eyes and pointed at him with satisfaction. "Thank you. Our perp wants to be clear. He wants us to understand him. If there are several possible explanations for a situation, the most likely explanation is usually correct. It is, therefore, a matter of sequence. He has made a list, which he is now diligently working through, leading us directly to the next question. Which one?"

The way Elizabeth conducted her meetings could seem strange to an outsider. However, most homicide detectives quickly became accustomed to her idiosyncratic style after her promotion to captain. In fact, most of them really liked her now.

Nikki cleared her throat. "If it's a list, the question arises as to why he doesn't work through it chronologically. So far, we have orders seven, four, six, five."

"That's right, Detective O'Laighin," the captain confirmed to her daughter. "How do you like the nickname Quentin?"

"Why is that?" replied Nikki, who had put herself forward for the detective exam shortly after her return to the BPD and had passed it with flying colors.

"After Quentin Tarantino. Pulp Fiction. That movie isn't told chronologically either."

Nikki rolled her eyes and shook her head but grinned. "Can it get any more complicated than that?"

"All right," Elizabeth ignored her daughter's objection. "Why doesn't he kill in the right order? The most likely answer is that it's not possible for him. He can't proceed according to chronology; he has to follow favorable opportunities. He is obviously in a great hurry. So, it would slow him down if he had to work through his list strictly from top to bottom. The interesting thing is that this realization tells us something important again. What?"

"It tells us that he's a ruthless sociopath who has worked out a totally insane plan and, despite all the madness, actually manages to control himself so well that he doesn't make any mistakes," Nick replied with a frown. "Why don't we call him Counter Killer?"

"Why not Monk with the numbers." Elizabeth looked at her brother-in-law closely. "Abstaction, Sergeant. Of course, he's a sociopath; we'd know that even without his unchronological sequence of numbers." She stood beside Castella's chair and said without looking at her superior. "By abandoning the correct order of his list, he reveals that he doesn't choose just any victims, but particular ones. But who does he leave the numbers at the crime scenes for? For the dead?"

"For the living," Mike answered.

Elizabeth seemed satisfied. "By leaving a coded message to the living through the numbers, he's telling us that his victims are only the means, not the end. So now let's bring these two insights together: He chooses particular victims and sends a message to the living by murdering them. What do we know from this?"

Nikki looked closely at her mother before answering. "Whatever he's trying to communicate through his murders must be obvious enough for us investigators to understand. He doesn't know his victims or barely knows them. He has chosen them because they symbolize something in his eyes. They stand for a quality that any outsider can unmistakably recognize."

Instead of answering, Elizabeth applauded, left her position next to Castella, and walked forward to her laptop, which she had connected to a projector.

She had prepared pictures of the four people who had fallen victim to the serial killer so far. First, she projected a picture of the Frenchman Pierre La Maire on the wall. "You can assign an obvious transgression to each of the four victims. Let's start with the first: La Maire produced foie gras. You can hardly be more barbaric with living creatures, and he has been heavily criticized for this at the fair in recent years. For our murderer, he is obviously a symbol of cruelty to animals. This is also supported by the fact that he had him killed by animals." Without waiting for questions or reactions, she projected a picture of the second victim onto the wall. "Oliver Cramer. At first glance, a simple welfare recipient. until you type his name into a search engine. Our dear Oliver has been in the newspaper at least eight times in recent years and has also been a guest on several talk shows. Why?"

Of course, the investigators knew the answer. Oliver Cramer was not a blank sheet of paper. The public prosecutor's office had investigated him several times.

"A social parasite," Mike explained, frowning a little. "He was collecting top rates of welfare every month, moonlighting, signing over assets to his girlfriend, and laughing at the stupid taxpayers on TV."

Elizabeth took a deep breath and nodded before posing the next question. "That puts Cramer in our line for --"

"Greed," Nikki said, raising her shoulders briefly.

The captain nodded in agreement. "I couldn't agree more. But what I still don't have an answer to is why the killer let him drown, of all people."

Nick took a deep breath and licked his lips. "He didn't. Cramer froze to death in the water."

Elizabeth licked her lips as well. "The life jacket was just a necessary evil for the perpetrator. Without it, the body would have sunk and disappeared in the low water temperatures for quite a while. But we're supposed to find the dead and quickly!"

"So he should have chosen a different method of death from the outset," Nikki pondered. "But he didn't."

"Excellent, Detective O'Laighin," Elizabeth agreed. "So now we know that it's not just the victims who are important for his message, but also how they die. And once again, the perpetrator had to make a compromise: The victim was supposed to drown. But because we would have found him too late, he had to settle for freezing to death. His symbol of death, in this case, is the water, not the cold."

She now projected a picture of the third victim onto the wall. "Norman Roberts, the arsonist. Our firebug was completely burnt. We wouldn't even know who the killer was if his murderer hadn't left us his rucksack near the car."

"Roberts was a car lighter. One of the few we've caught so far," Nikki added with a furrowed brow.

In recent months, there has been an increasing number of cases of unknown persons setting cars on fire indiscriminately in Boston.

While these crimes had initially been politically motivated and mainly directed against luxury vehicles, many criminals had soon switched to acting purely for the pleasure of destruction.

Vehicle owners and insurance companies have already lost millions as a result. The fires, which fortunately had not yet spread to surrounding buildings, repeatedly put people's lives at risk.

The Boston police had only rarely succeeded in arresting one of the arsonists. Norman Roberts was one of them.

"The court gave him probation," Nick said, looking at his niece with a furrowed brow.

Elizabeth threw a picture of the charred corpse on the wall and stated soberly, "His killer wasn't that accommodating. We found everything the boy would have needed to set fire to the Mercedes himself in Norman Roberts' rucksack. If you ask me, his killer didn't have to do it for him. The arsonist burning in his own fire. A clear message!"

"So, Rick Frye," Nikki noted. Of course, Elizabeth had also prepared a picture of the fourth victim. "A cat burglar forced to descend from a skyscraper with oiled hands."

"Just as clear," said Mike. "He climbed high - and falls low."

Instead of commenting on the interjection with words, Elizabeth imitated the sound that would be heard on a quiz show if a contestant had given a wrong answer. "What did you miss?"

The whole team was visibly shaken.

Two murders had taken place in just one night, and the prosecution had increased the pressure on Castella and, therefore, on Elizabeth, who had left no doubt that they wanted to see tangible results as soon as possible.

So, instead of trying to develop theories, the others preferred to wait until Elizabeth presented her ideas. "Victim number four is the first clear deviation from his previous pattern," the captain finally explained. "La Maire tortured animals, Cramer defrauded society, and Roberts destroyed other people's property. And Frye?"

There was silence for seconds until Nikki broke the silence. "He didn't harm anyone," she stated. "His climbing was stupid, reckless, risky - but he only put himself in danger."

Elizabeth looked closely at her daughter. "Which means we're not dealing with a perpetrator who wants to be punished according to the law, but --"

Nikki took a deep breath and closed her eyes briefly. "In the service of social morality."

Elizabeth looked at the younger woman closely, licked her lips, cleared her throat, and switched off the projector.

She sat in the chair at the head of the room, looked at her smartwatch, and closed the meeting by saying, "We're running out of time, people. So, why did he suddenly go on a killing spree? What was the trigger? Why is he in such a fucking hurry? What's driving him? How does he choose his victims? What other offenses are on his list?"

Only now did Castella stand up, slam her notebook shut, and call out from her seat beside Nikki. "If you can, Captain, I would be delighted if you could answer this question and catch the perpetrator before the next body turns up." She then walked forward with firm steps and addressed Elizabeth personally. "Please come straight to my office."

Then, she again addressed all other investigators in the special task force. "We'll call him Jack from now on after Jack the Ripper. But our Ripper will not escape. Do we understand each other?"

Elizabeth took a deep breath and hung her head.