A prostitute has been brutally murdered, and the police believe they have found the murderer. Fitz, DS Jimmy Beck, and DS Jane Penhaligon are assigned to work on the case. While their suspect is in custody, a second identical murder takes place. They believe a confidant of the suspect has committed the second murder in order to clear his name. They question the suspect's wife and brother, but meanwhile, a third identical murder takes place. Fitz is visited by his brother, who tells him their mother has died.