A serial killer that decapitates people is on the loose in the Stockholm subway. Martin Beck and his colleagues try to catch the killer, while the panic in the city increases.

The Beck group, with Alex Beijer as new group manager, is given a case where a 12-year-old girl found her mother dead below the stairs at home. Is it an accident or would someone have the single mother something bad? It turns out that the family lives with a protected identity and during the investigation, the case takes several surprising twists.

The bodies of two buried men are found and despite persistent attempts, they cannot be identified. When another man is murdered they discover new evidence that soon leads them to an Islamist terrorist cell.

When a well-known crime boss is murdered by a sniper in front of his family, Beck and his team are challenged to discover which one of his many enemies could be responsible for the crime.

The body of a young woman is found in a Stockholm hotel room. It appears that she has been strangled after a night partying with two young men, but the room was paid for using the credit card of a mugging victim whose alibi doesn't add up. Martin and Gunvald investigate under the supervision of their new boss Klas Freden.

Two traffic officers on a quiet morning shift try to stop a car for speeding. When the car finally pulls over, the driver gets out and shoots at them, killing one of the officers in cold blood. A national alert is issued and an extensive search for the ruthless killer begins, with the Beck group at the lead. Neither the officer’s shocked and wounded colleague nor any of the witnesses have seen anything helpful to the police. Finally, they find the car registration number using a surveillance camera. But, when they enter the car owner’s apartment, they find him shot to death. The first day of summer is a long one for the Beck group, as the killer has more victims on his list.

An unidentified body is found in the remains left after a fire in a trailer at a run-down caravan park. The owner of the trailer, a young drug-addicted woman, is missing, but is she really the victim? And what role has the so-called neighbourhood watch from the nearby community played? The case is difficult to solve, with everyone involved guarding their secrets, regardless of social class. Furthermore, police supervisor Klas Fredén decides to go over Martin Beck’s head and recruit charismatic, Norwegian homicide investigator, Steinar Hovland. The newly-structured Beck group faces the blight of a power struggle. And Martin struggles to find his way back to his old self.

A man is beaten to death in the Middle East. In Stockholm, a young woman disappears on her way home from work. These two events will prove to be related. Since Martin Beck has quit, Steinar Hovland leads the search for the missing girl. But Martin is drawn into the case when he decides to help the national Security Police investigate a suspected terrorist. They soon realize that they are in a race against time to stop a catastrophe.

Simon Lindström, the popular coach of a suburban junior hockey team is found stabbed to death. Does the murder have something to do with his side project: teaching unaccompanied refugee children to ice skate? This undertaking has certainly not been appreciated by everyone in their small, sheltered community. Martin Beck, who has returned in a more senior position, struggles to find a replacement for the temporary head of the group, Steinar Hovland. But the Norwegian is becoming more and more interested in keeping his new role. The question is whether Martin can trust him?

A jawbone is found in the middle of the forest. When the rest of the body is found, it turns out that it has just recently been moved and belongs to Viktor Eklund, who has been missing for five years.