It's Saturday night at an old Hospital in Helsingborg. Karin Bellman is a bit forgetful and has been admitted with an injury to her arm. Her husband is by her side and introduces himself as doctor in theology but in the weekend stress he is mistaken for a doctor in the hospital and is put to work.
In a playground in the centre of the urban idyll, the police find a buried wooden box containing a famous and well-respected prosecutor. Martin Beck and his police team initially suspect a highly criminal MC-leader of the attack, but one pretty soon has to re-evaluate the case once the MC-leader is found murdered in a similar wooden box. Soon, more wooden boxes are found and the police realize that they are part of a cat and mouse game with a crazy serial killer. The investigation soon shows that there is a vague connection between the victims in the shape of a 9 year old event, but what Martin Beck does not suspect is that his own life too is at stake, as the murderer has chosen him as the next victim.
Swedish politician John Veden vanishes without a trace. There's no hint he's dead yet but Beck's team gets the case due to Police Chief Oberg's friendship with the man whom she dined with him the evening before he vanished. When they find out Veden was a gambler with heavy debts battling his addiction the case leads Martin Beck, Gunvald Larsson and freshly returned Lena Klingström into Sweden's illegal gambling scene. And Veden was planning to expose his own addiction and his party's huge financial profits from gambling in a confessional book - which his political allies got wind of via illegal data theft. With several people having an interest that Veden stays missing the team tries to find the politician and the true perpetrator while Beck is grappling privately with his ambivalent feelings about working with ex Lena again....
Two patrolling cops stumble on to three criminals who have just stolen large amounts of explosives, and are killed in cold blood. Martin Beck and his team must now work day and night to find out who the killers are and what they are planning to do with the explosives before it's too late. Meanwhile, Gunvald Larsson who was a close friend of one of the murdered cops is ignoring all rules in his quest for revenge.
