Inspired by actual events, when high school football hero and decorated policeman’s son Jimmy Keene (Taron Egerton) is sentenced to 10 years in a minimum security prison, he is given the choice of a lifetime — enter a maximum-security prison for the criminally insane and befriend suspected serial killer Larry Hall (Paul Walter Hauser), or stay where he is and serve his full sentence with no possibility of parole. Keene quickly realises his only way out is to elicit a confession and find out where the bodies of several young girls are buried before Hall’s appeal goes through. But is this suspected killer telling the truth? Or is it just another tale from a serial liar? This dramatic and captivating story subverts the crime genre by enlisting the help of the very people put behind bars to solve its mysteries.