When a police officer with a tablet addiction sees a dead boy, she questions her sanity, but she realizes that she is facing victims of unsolved crimes and that her past can help to catch a killer on the loose.

A body is found in the water near Liljeholmen. The body belongs to a 39-year-old Danish citizen with a solid criminal record and who was a member of a notorious Danish drug gang. Should the Beck Group get a gang war on their necks? Martin Beck is back to the joy of the entire Beck group. Martin's daughter Inger is not as happy but has to accept her father's decision to start working again.