A woman is found murdered in a closed amusement park. A young couple who happen to be there at the same time become, without their knowledge, suspects for the murder. They are chased by a large number of police but only Martin Beck believes them to be innocent.

A psychiatrist temporarily separated from her family begins to experience severe psychological distress while working at a mental hospital and returning to her childhood home. As her professional responsibilities and personal relationships intersect, she undergoes a breakdown that forces her to confront long-suppressed memories and fears.