DCI Cassie Stuart, one of the Met’s smartest detectives, has to investigate an old crime with her partner, DI Sunil Khan. They find a diary with the bones of a young homeless boy. His diary implicates four suspects; a clergyman, an eminent entrepreneur, a community worker and a wheelchair-bound husband caring for his wife. Each has a secret to hide. As their lies unravel, the people they love most begin to wonder what else they might be capable of. Nothing in this case is black and white. Can you ever really know the people closest to you? What secrets have they buried?