A young man has been found murdered and the Beck group's work with the murder points in the direction of a drug network. Klas Fredén has been spying on this network for a long time, and he does not want his investigation, which is in a critical phase, to be jeopardized. However, he allows the Beck group, led by Alex Beijer, to work with the murder investigation in parallel with the reconnaissance. This causes Alex to end up on a constant collision course with Fredén. The conflict causes Martin Beck, now Rotel chief, to become involved in the work of his former group, something that enlivens him. Steinar is having a harder time, torn between work and longing for his children in Oslo. The pressure on the Beck group becomes fierce during the season, both with tough investigations and emotional changes in the group.

A candidate for the Nobel Peace Prize is brutally stabbed to death in central Stockholm just after a meeting with two lawyers from the war tribunal in The Hague. One of the witnesses worked with Alex when she was stationed in the Middle East and they have an attraction to each other that makes Josef think she should stay out of the investigation. But Klas Fredén is pressuring the group to resolve the politically charged case before SÄPO takes over. Martin Beck is on sick leave but continues to go to work waiting for a diagnosis. He, Oskar and Jenny are forced to relate to the growing tensions within the group and it soon turns out that several of those involved carry dangerous secrets.