"Dark Places" is a mystery novel written by Gillian Flynn, published in 2009. The story follows Libby Day, the sole survivor of her family's brutal murder when she was a child. As an adult, she is haunted by the traumatic event and is drawn back into the investigation when a group of amateur detectives seeks to uncover the truth about that night. The narrative alternates between Libby's present-day quest for answers and flashbacks to the night of the murder, revealing the complexities of her family's dynamics. The novel explores themes of trauma, memory, and the impact of violence, while also delving into the lives of characters like Ben Day and Patty Day.