The body of a young Brazilian woman is found strangled with a tie in a forest where three similar murders occurred several years before. Barnaby and Troy visit George Meakham, the now-retired police officer who was in charge of the investigation of the earlier crimes, and who has since become obsessed with them. The trail leads them to a local cigarette and tobacco company and two of its employees in particular. The Portuguese au-pair of one of them is then murdered. Barnaby manages to solve both the new murders and the old ones, though not before the murder of yet another victim. Guest starring Phyllis Logan (Downton Abbey).