An unidentified male corpse, with a wooden stake hammered into its heart, has been pulled from the Peak Forest Canal at Lock Number 9 in Marple. Detective Inspector Josiah Dark has been sent to investigate. The initial chaos at the crime scene is compounded by the unexpected return of his unwanted partner - Detective Constable Annie Lake. Leads are hard to come by, but eventually they begin to unearth a web of bribery, corruption and murder from fifteen years previously. Also, the two people helping him to find out the truth about his wife Ellie - the investigative reporter Dixie Reyes and her partner Hendrik Larsson - have stumbled onto the deaths of old people without relatives who have all their money transferred from their bank accounts days before they die. Morbid Maud - Professor Finn's assistant at the mortuary in Wythenshawe Hospital - asks him to look into the case of her nine year-old sister, who was abducted from Blackpool seafront three years ago. And then, of course, there's the suggestive photographs of Ellie that Hendrik has found . . .