Carl and Assad achieved a measure of success in their first case, so the powers-that-be must tolerate them, while not moving them out of their basement dungeon or giving them any actual benefits. To "help" with his duties, Carl has been assigned an additional person, Rose, a woman who washed out of the police academy but qualified to hold a civilian job with the department. And, yes, she's very odd. "Q" apparently stands for qnot-qwanted-qanywhere-qelse. It would have been fine had the book been mostly about them, but it's mostly not.
Adler-Olsen takes us into the minds of a group of psychologically stunted, high-achieving individuals, a group of men and one woman who have known each other since a sick bond was forged in prep school. Kirsten-Marie Lassen, "Kimmie," has not had direct contact with the men for quite a while when the story starts. She's living on the streets but seems to have a lot of money. She's afraid, yet she's also a stalker.
Right from the start, Adler-Olsen takes most of the mystery out of the story. The case Carl and Assad decide to investigate is the murder of a brother and sister about twenty years earlier. One of the group confessed to the crime nine years later, and he currently languishes in prison. Carl and Assad become convinced that there is more to the story, and that's how they discover the group. As teenagers they were emotional and physical bullies. The key to unlocking the group dynamic seems to rest with Kimmie, so the book is really about finding Kimmie and discovering what makes her run.
The story is too long.
Too much from the point of view of Ditlev Pram, a private hospital entrepreneur, Torsten Florin, a fashion designer, and Ulrick Dybbøl Jensen, a stock market analyst. Kristian Wolf, a shipping magnate, is dead. Bjarne Thøgersen is in jail. They're sick. Let's not dwell too long on their inner workings. They want to find Kimmie and Kimmie wants to find them. Bam. Move along to the hunt.
Let's get back to Carl and his dysfunctional department. A group of Norwegian police representatives want to visit Carl to talk about his spectacular police work. Carl's bosses want to limit access to him because he's grumpy and unpredictable. Carl has no interest in meeting the unintelligible Norwegians anyway, but the inevitable must happen. It's a humorous touch to lighten what is a heavy load.
The relationship between Carl and Assad is slowly evolving. Into what probably won't be seen until a future book. Here Adler-Olsen simply is establishing that there's more to Assad than meets the eye. This partnership is what makes the series, and it's enjoyable to watch them track down the group and discover just what crimes the members have committed.
Warning: There are many graphic scenes and the resolution is particularly gruesome. Just so you know.