 The team reopens the case of the murder of a young wages clerk at Battersea Power Station in the 1950s after the daughter of the man hanged for crime starts a campaign to have him posthumously pardoned. When an aristocrat who was the key witness retracts his statement and a suitcase of cash is found in the alleged culprit s attic, the team suspects there was a blackmail plot involved and questions the validity of the original case.