In 2005, Otis Lort is a movie star who has an extreme alcohol problem. He crashes his car and gets into a violent, drunken altercation with police. He is forced to go to a rehab facility, where his counselor, Dr. Moreno, tells him that if he leaves the facility before they say he is ready, the court will send him to prison for his violent offenses. Dr. Moreno tells Otis that he has PTSD, which he denies repeatedly, but she encourages him to look into his past through exposure therapy.Going back a decade earlier to 1995, Otis remembers working as a child actor, who is accompanied on set by his father, James (Shia LaBeouf), a former rodeo clown. James is four years sober but clearly on edge and unpredictable, manic and aggressive. The two live in a meager motel complex where a shy young woman (FKA Twigs) lives across from them. Otis is in the Big Brother program at the behest of his mother, despite James's dislike and jealousy. Otis wants to go to a baseball game with Tom from the program, and James agrees if Tom comes over for a barbecue.To 2005 again, Otis is shown communicating with his rehab roommate Percy and continues therapy. He resists the process, finding it unhelpful. Back to his memories, Otis remembers Tom coming over for the barbecue, and James throwing him into the pool and violently threatening him. When he is offered a part in a movie that will be shot in Canada, Otis calls his mother, who isn't sure if James can accompany him because he's a registered sex offender. This causes James to begin screaming at her via Otis, who has to relay both of his parents conversations back to each other.Back to present, after resisting yet again, Otis's counselor Alec advises him to go into the woods and scream as loud as he can. Then the film shows James attending an Alcoholics Anonymous meeting, where he tells of his abusive stepmother, how he got into drugs and alcohol abuse, and while blacked out attempted to rape a woman which got him registered as a sex offender. Alone at his place, Otis spends time with the Shy Girl, and the two cuddle and he gives her money.James forces Otis to rehearse his scenes over and over again, and he stops to scream at the neighbors across the way for being too loud. Otis asks him to stop, and tells him that no one else would hire him because he's a sex offender, and that Otis is his boss since James is making money off him. In 2005, Otis thanks Alec for the advice, and continues to work with Dr. Moreno on controlling his anger.In 1995, Otis finally confronts his father and tells him he needs to start being a better dad to him. James hits him in the face twice, furious at Otis for speaking to him that way, and then leaves on his motorcycle and scores drugs at a strip club. Alone, Otis spends time with the Shy Girl, and the two are caught waking up together the next morning by James. The Shy Girl slaps James and leaves, and James vomits and asks Otis how he thinks it feels to hear his own son talk to him like that, and to have to resort to accepting payment from him. Otis tells James if he didn't pay him James wouldn't be there.James takes Otis to marijuana plants he has been growing off the highway and smokes cannabis with him. In 2005, Otis revisits the motel, and imagines himself finding his father there in his rodeo clown costume. He tells his father he's going to make a movie about him. James asks him to make him look good. The two ride away on James's motorcycle, which fades into Otis alone driving away.