High-flying financiers are being murdered and it is beginning to appear like the work of a serial killer, prompting the formation of a special police unit.

Three businessmen are murdered on consecutive nights, sending the financial world into a panic and putting the A-Unit under immense pressure.

Without knowing the identity of an American serial killer who's on a plane flying from New York City to Stockholm, the A-Unit tries to find him.

A Unit continues to hunt for the Kentucky Killer, the infamous American serial killer who is now on the loose in Sweden. The FBI are called in to help with the investigation.

While vacationing in the Netherlands, a Swedish family is killed by a car bomb and it's up to the A-Unit to solve the case.

When an illegal African immigrant is shot and killed by police, Kerstin Holm is assigned the task of interviewing the police officer. He happens to be her ex-boyfriend Dag Lundmark, who then disappears without a trace during the investigation.

A Unit discovers a link between the shooting of an illegal African immigrant, bodies found in a marsh in Varmland and an apparent suicide. Kerstin Holm tries to track down missing police officer Dag Lundmark single-handedly. Suddenly she realises that he has come across a terrible secret and is just waiting for her to find him.

The A-Unit has its hands full when celebrated Jewish neuroscientist Leonard Sheinkman is found murdered, strung up from a tree in a Jewish cemetery; a group of women escape from an immigration board hostel, where they are being exploited as prostitutes, and flee the country; and a body is found half eaten in the wolverine enclosure of a Stockholm zoo.

When Söderstedt is sent to Italy in pursuit of leads linked to the wolverine killing, he crosses paths with a treacherous Mafia boss. Soon he finds himself in Germany following up leads from the murdered Leonard Sheinkman's war diaries, while also trying to unravel the mystery of the inheritance he has received from his uncle.