The Lost Child

S4, E1: Comprising three two-hour films, the newly promoted Detective Superintendent Tennison is assigned to different stations to head up major enquiries. 'The Lost Child' sees Tennison back at Southampton Row to work on a case involving the disappearance of a young child. Tennison's enquiries lead her to a serial child sex offender, who takes a woman and her two children hostage. 'Inner Circles' takes Tennison to an affluent suburb of London to investigate a bizarre death. The case exposes fraud, corruption and the hollow relationships that lie beneath the respectable veneer of the community. 'The Scent of Darkness' sees the relationship between Tennison and the criminal psychologist Patrick Schofield develop into a promisingly happy affair. A series of murders takes place resembling cases Tennison has previously investigated. In the face of a possible finding of a miscarriage of justice, Tennison may find herself suspended.