Morse and Lewis investigate the death of Jackie Thorn who was found bound and stabbed in her flat. The murder is a carbon copy of one that occurred 27 days previously and they assume both were committed by the same man. The team is joined by Sgt. Siobhan Maitland, a expert in crimes against women. In the course of the investigation, they find that both women had purchased their cars from the same dealer and Morse becomes convinced that the owner, Jeremy Boynton, is the culprit. When they find a third assault victim who survived an attack some 5 years previously, Morse is more convinced than ever. The only thing now is that Morse needs evidence, provided he has the right man of course.