The sole survivor of a home invasion where she famously witnessed the death of her mother and sisters, Libby Day (Charlize Theron) lives with the knowledge that her testimony as a 7-year-old sentenced her brother, Ben (Corey Stoll), to life in prison for the horrific crime. Twenty-five years later Libby meets Lyle (Nicholas Hoult), the head of a group of true-crime enthusiasts, The Kill Club, who convince her to re-examine the events of that night. As new memories and old suspects flood back into her life, Libby begins to question her own testimony and sets out to discover the truth of her tragic past.The screenplay, by Paquet-Brenner, is based on Gillian Flynn's 2009 novel of the same name.