One night in 1994, Carrie Walsh returns home from a party to find her prostitute mother Sally murdered. Carrie sees a man's shadow on the wall and, whilst phoning the police, observes a man with a bloodstained hand. She is keen to help DI Douglas Hain in his investigation, though the crime ultimately goes unsolved. Fifteen years later, Carrie, now known as Carol, is about to get married. She goes to visit Hain to help put the tragedy of her mother's murder behind her.