Based on the book Core of Evil by Nigel McCrery. Detective Chief Inspector Mark Lapslie and Sergeant Emma Bradbury are called to the scene of a car accident, but that’s not the reason they are there. The accident uncovered the decomposed body of a woman. Lapslie, doesn’t understand why the case has been assigned to him. DCI Lapslie is a solitary man, but not by choice. Living with a rare condition known as synaesthesia, he can literally taste sound. As he investigates, he is aware of being watched. Once he discovers there is a serial killer at work, his superiors want him to back off.