When two bodies surface in the garden of a rented house in North London, Forensics discover fingerprints which link back to an unsolved crime that no one in the Metropolitan Police wants to remember. More than a decade ago, in an isolated holiday cottage in Sussex, a family was found brutally slaughtered. The prime suspect was Callum Carmichael, the father of the family and a police officer from the Met's own ranks. But without enough evidence to arrest him, the case was hushed up and the trail left to go cold.
