'He could feel it in the blackness, a difference in atmosphere, a sense of evil, of things hidden.' Amy Snowden, in middle age, has long since settled into a lonely life in the Yorkshire town of Gunnarshaw, until – to her neighbours' surprise – she suddenly marries a much younger man. Months later, Amy is found dead – apparently by her own hand – and her husband, Wright, has disappeared. Sergeant Caleb Cluff – silent, watchful, a man at home in the bleak moorland landscape of Gunnarshaw – must find the truth about the couple's unlikely marriage, and solve the riddle of Amy's death.