Libby Day was just seven years old when her older brother massacred her family while she hid in a cupboard. Her evidence helped put him away. Ever since then she has been drifting, surviving for over twenty years on the proceeds of the 'Libby Day fund'. But now the money is running out and Libby is desperate. When she is offered $500 to do a guest appearance, she feels she has to accept. But this is no ordinary gathering. The Kill Club is a group of true-crime obsessives who share information on notorious murders, and they think her brother Ben is innocent.

It is 2 January 1985 - the day of the murders. Ben is a social misfit, ground down by the small-town farming community in which he lives. His family is extremely poor, and his father Runner is violent, gambles and disappears for months on end. But Ben does have a girlfriend - a brooding heavy metal fan called Diondra. Through her, Ben becomes involved with drugs and the dark arts. When the town suddenly turns against him, his thoughts turn black. But is he capable of murder?In a brilliantly interwoven plot, Gillian Flynn keeps the reader balanced on a knife-edge, as Libby delves into her family's past and Ben spirals towards destruction.