Trama

Libby Day was only eight years old when her family was brutally murdered in their rural Kansas farmhouse. Almost thirty years later, she reluctantly agrees to revisit the crime and uncovers the wrenching truths that led up to that tragic night.

Libby Day was only seven years old when her mother and two sisters were brutally murdered in their rural Kansas farmhouse. In court, the traumatized child pointed the finger at her brother, Ben, and her testimony put the troubled 16-year-old in prison for life. Twenty-five years later, a broke and desperate Libby has run through donations from a sympathetic public and royalties from her sensational autobiography, without ever moving past the events of that night. When Libby accepts a fee to appear at a gathering of true-crime aficionados led by Lyle Wirth, she is shocked to learn most of them believe Ben is innocent and the real killer is still at large. In need of money, she reluctantly agrees to help them reexamine the crime by revisiting the worst moments of her life. But as Libby and Lyle dig deeper into the circumstances surrounding the murders, her recollections start to unravel and she is forced to question exactly what she saw--or didn't see. As long-buried memories resurface, Libby begins to confront the wrenching truths that led up to that horrific night.—A24 Films

Convinced that her brother Ben dabbles with the occult, Libby Day, the sole survivor of a brutal family massacre in 1985, accuses him of being the killer. Nearly three decades later, with Ben rotting in prison, Libby agrees to open up to true crime enthusiast Lyle Wirth and tell her side of the story. But instead of finding answers and closure, Libby begins to question everything as she explores her painful past. Could the murderer still be out there? Are there more sides to the truth than she ever knew?—Nick Riganas

In 1985 in Kinnakee, Kansas, Libby Day is the sole survivor of the massacre of her mother and two sisters. Responding to the police's leading questions, she tells them that her brother Ben (Sheridan) committed the crime. In the present day, Libby (Theron) has made a living from donations sent by strangers to the little girl they saw on the news. With donations drying up, she is hard up for cash when she is approached by Lyle Wirth (Hoult) to make a personal appearance at his "True Crime" club. She agrees to go and answer questions about her past for $700.

Back in 1985, Ben comes to the breakfast table with his hair dyed black. He has a tense relationship with his mother Patty (Hendricks) and his eldest sister Michelle, who taunts Ben about being a loner and rumors about him at school. Ben hangs out with a Satanist bookie named Trey Teepano. Meanwhile, their mother Patty is told that her farm is being foreclosed on, despite her best efforts to stay afloat.

At Wirth's club, Libby learns that most of the members believe her brother Ben is innocent. His conviction was based on Libby's testimony. Still believing that Ben is guilty, Libby nevertheless agrees to work with the club in return for much needed money. Urged by Wirth to visit Ben in prison, Libby's curiosity about what motivated him to kill their family prods her to keep researching the case.

Prior to the murders, Ben was planning to run away with his pregnant girlfriend Diondra (Moretz). Meanwhile, several young girls have accused Ben of molesting them. When Patty is informed of the charges, she visits the home of the chief accuser Krissi Cates, whose father is irate and looking to harm Ben. Patty is distraught by the accusations and feels that she has failed her kids. Back home, their father Runner (Bridgers) is waiting for Patty. He needs money to skip town because he owes Trey more than he can repay. He is violent and abusive towards Patty. He attempts to rip her heirloom ruby necklace off her neck but, unable to do so, he abuses her and steals money from her wallet.

In the present, Libby tracks down Runner to an abandoned factory where he lives with other homeless addicts. He tells her about Diondra's pregnancy. Libby also locates Krissi Cates (Matteo), who eventually confesses that she made up the molestation accusations against Ben.

Meanwhile in 1985, Patty is informed by a friend with the Farmers Home Administration that he might have a solution to her problems. She meets with a stranger in the middle of the night who says that he can help her. It later turns out that he is Calvin Diehl, a serial killer known as the Angel of Debt, who murders people so that they can collect on their life insurance policies. Patty goes home and hides some money for Diehl.

At the same time, Diondra finds out about the accusations against Ben and convinces him to flee with her immediately. They go to Ben's house to steal some money. Michelle overhears them talking and threatens to tell on them. Diondra viciously attacks Michelle and starts to choke her. Diehl has also entered the house. In the hallway, he stabs Patty. When her middle daughter rushes out of the bedroom to get help for Michelle, Diehl grabs the family shotgun and kills the young girl. The shot distracts Ben from his effort to protect Michelle. While he goes to see what has happened, Diondra kills Michelle.

In the present, Libby finds Diondra and the daughter she had with Ben. She finds her mother's ruby necklace in Diondra's bathroom and realizes she is in danger. Diondra's daughter attacks her, but she manages to escape the house. She finds out about Diehl's involvement from Wirth, whose club has been working on the Angel of Debt case. Libby visits Ben again in prison, and they apologize to each other. She realizes he was trying to protect his unborn daughter by taking the rap for the murder of his mother and his sisters. A news report confirms that Diondra has been arrested. Libby returns to look at the family farm where she grew up. Ben is exonerated and released from prison while Libby states that she doesn't intend to press charges against Diondra's daughter who has yet to be found as she understands her actions.