Detective Inspector Montague Pluke of CID is England's most superstitious police officer. With crime at its lowest level in years, he decides to conduct a cold-case review. But there are no major unsolved crimes. So, alerted by his wife, Millicent, to a large number of recent deaths, his expert knowledge of superstitions and folklore lead him to justify reopening a case. Could an undetected mass murderer be operating in Crickledale? Many of the deceased attend Crickledale Voluntary Carers, and he quickly produces a list of possible suspects. Indeed, the entire team of carers falls under suspicion - and Millicent is one of them.