A man is found dead in a canal in Copenhagen. Preliminary indications suggest he drowned or died of hypothermia. Soon, however, the coroner confirms it was a murder. Inspector Leif Anders Pedersen starts his investigation.
Several clues lead him to a suspect who has well-founded reasons to have killed the victim and so the mystery murder seems to be solved.
Unfortunately, the following day the police finds another body in a boat stranded in another canal. The only thing in common between the victims is their Swedish nationality.