The film opens during a wrestling match, where Jack Adkisson, better known by his stage name Fritz Von Erich (Holt McCallany, uses his signature “Iron Claw” move on his opponent’s face. He later meets with his wife Doris (Maura Tierney) and sons Kevin and David. Doris is displeased with Fritz using more money than they needed to spend on a flashy new car. Fritz promises to only provide the best for his family.
Years later, Kevin (Zac Efron) is following in his father’s footsteps to enter the wrestling world. Fritz expresses favoritism towards his son Kerry (Jeremy Allen White) since he is a prospective Olympian. David (Harris Dickinson) also wrestles, while Fritz is trying to get youngest son Mike (Stanley Simons) into the sport, despite his preference for music. Kevin tells Doris that Fritz is too hard on Mike, but she dismisses his claims.
Kevin and David enter a tag-team match against Bruiser Brody (Cazzey Louis Cereghino) and Gino Hernandez (Ryan Nemeth) at the Sportatorium. Both brothers put in the effort, with David utilizing the Iron Claw on his opponent. After the match, Kevin is approached by a young woman named Pam (Lily James), who is interested in him and gets him to ask her out. They go out for a meal, where Kevin tells Pam about the supposed curse in his family. He talks about the original oldest Von Erich brother, Jack Jr, who died when he was six. Pam gest closer to Kevin’s side to comfort him.
Kevin and David later compete against Harley Race (Kevin Anton), where Kevin receives a heavy thrashing and only wins because Harley is disqualified after throwing the ref out of the ring. Fritz shows disappointment toward Kevin but pride toward David and his talents.
Due to the 1980 Olympics boycott, Kerry’s chances of being an Olympian are taken away. Fritz tries to encourage him to compete in the ring alongside Kevin and David. Later, the brothers get ready to go out for one of Mike’s music gigs, with help from Pam on sneaking them out so that their parents don’t know where they are going.
By the early 80s, the three brothers have made names for themselves, defeating the Fabulous Freebirds in a six-man tag-team competition. Later on, Kevin and Pam get married. During the reception, Kevin finds David vomiting into a toilet with a hint of blood shown. While David claims he is fine, Kevin tells him first that Pam is pregnant, which will make David an uncle, something he is excited for. Sometime after, David goes touring in Japan, but Kevin comes home one day to find Fritz alone, who tells him that David died from a ruptured intestine. The family mourns David at his funeral.
David was supposed to fight Ric Flair (Aaron Dean Eisenberg) for the world championship title. Fritz does a coin toss to decide between Kevin and Kerry to take David’s place, and the coin lands on Kerry. He takes on Flair and defeats him, winning the title, but it is clear he is facing an internal struggle. Kerry later goes out for a motorcycle ride and collides with a truck, causing him to lose his right foot. Kerry continues training but is brought down repeatedly by his handicap.
Fritz makes Kevin start training a reluctant Mike to follow in their footsteps. During his first match, Mike suffers a serious shoulder injury, and the ensuing toxic shock syndrome causes him to fall into a coma. When Mike eventually wakes up, he has signs of brain damage. Kevin is convinced the family curse is real, and he goes to have his newborn son’s name legally changed to Adkisson. Fritz then tells Mike to get himself back into the ring despite his injury. Mike is later seen writing a note and taking pills with a beer. His body is later found by his family.After Mike’s death, Kevin starts to become distant from Pam and their son. He is put in a match against Flair for the championship title and nearly suffers a loss at Flair’s hands, but Kevin overpowers him. However, he gets disqualified when he does the Iron Claw on Flair’s face for too long even after the ref ended the countdown.
Kerry continues trying to wrestle, with Kevin attempting to help him. Fritz wants Kevin to take over the World Class Championship Wrestling association, even though he has another son that he is raising with Pam. During Christmas, Kerry joins the family and gifts Fritz a new gun, but he starts to get belligerent when Fritz opts to put the gun away instead of firing it. Kevin tries to calm his brother down.
Sometime later, Kerry calls Kevin, talking to him about the family curse and his contemplating suicide. Kevin tries to locate Kerry and calls Fritz for help, but he is dismissive over his son’s fears. Kevin goes to the family’s old house the next morning, where he hears a gunshot. He runs over to a tree and finds that Kerry has shot himself in the chest. As he frantically tries to help his brother, Fritz arrives, and Kevin attacks him in a rage, blaming him for what happened to his brothers. Kevin carries Kerry’s body into the living room.
Kerry is shown arriving in the afterlife on a boat, where he finds Mike with his guitar, and David with his championship belt. The three also meet Jack Jr (Romeo Newcomer) for the first time and acknowledge him as their big brother.
Not long after, Kevin sells the WCCW to Jerry Jarrett to focus on his family. Doris starts to take up a painting hobby while it’s clear that her marriage to Fritz is over. Kevin later sits outside with his sons while they play football, and Pam is expecting a third child. Kevin starts to cry, and when his boys ask him why, he says he misses his brothers. The boys say they will be his brothers, which brings Kevin some comfort. He then joins his sons in the game.
The ending text states that the Von Erich family was inducted into the WWE Hall of Fame in 2009, and they remain one of the most influential families in wrestling. Kevin and Pam own a ranch where they let their whole family (four kids and thirteen grandchildren) live, accompanied by a photo of their large family.