An investigative journalist is found beaten to death in his home, where the fingerprints of a notorious criminal debt collector are also found. The murdered journalist has been threatened by right wing extremists, but it is the victim's work with a book about "society's dark side" that captures the Beck group's interest. When the case takes an unexpected and terrible turn, there is suddenly much more at stake than finding the journalist's killer. Martin Beck and his colleagues have never had to protect the balance of their professional and private lives with the same tenacity as they do now.

Three brutal murders are committed in a house in a quiet suburb. The victims are a former police officer, his wife and their 10 year old son. The Beck group takes on the case and find that there is a hidden security room in the victims' house, containing stolen weapons. They find fingerprints from a criminal who was involved in a robbery 4 years ago. After the robbery, he shot his accomplices and disappeared without a trace, along with their haul of 6.3 million.