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.
