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.

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.