Private detective Cormoran Strike is visiting his family in Cornwall when he’s approached by a woman, Anna Phipps asking for help finding her mother, Margot Bamborough, who went missing under mysterious circumstances in 1974. Never tackling a cold case before, he’s intrigued and takes it on, adding to the long list of cases that he and his partner are currently working on. As Strike and Robin investigate Margot’s disappearance, they come up against a fiendishly complex case with a psychopathic serial killer and witnesses who cannot all be trusted.