The story is adapted from the novel of the same name by Mara Leveritt, and is based on the real events of the "West Memphis Three". That is, the story behind a horrific murder case in Arkansas, USA in 1993: On the evening of May 5, 1993, three 8-year-old boys disappeared in a small town in West Memphis, Arkansas. Three "bad youths" Jessie Misskelley Jr., Damien Echols and Jason Baldwin were identified as suspects and were imprisoned for 18 years. In August 2011, after 18 years in prison, the "West Memphis Three" were released. Reese Witherspoon plays the mother of a victim in this film. At first, she firmly believed in the results of the police investigation, but as the case deepened, she gradually began to doubt the fairness of the case. Colin Firth plays a private detective in the film. He was a supporter of the defendant from the beginning and, through investigation, he presented crucial evidence. He has been supporting the defendant for free and was subjected to various abuses at the time.