Helena Lanark is the only one who knows about the horrors which once occurred in her family's house. The heiress of an immense family fortune, she now resides in a luxurious care home; her mind and memory fading fast. Jane Tennison is leading a murder investigation into the recent brutal death of a young girl, her decomposed, starved body discovered in an old air raid shelter in the garden of the Lanark's now derelict house. Initially the focus is on identifying the victim, until another body is found hidden in the walls of the shelter.