An ex-Marine haunted by a tragic past, Tommy Riordan (Tom Hardy) returns to his hometown of Pittsburgh and enlists his father (Nick Nolte), a recovering alcoholic and his former coach, to train him for an MMA tournament awarding the biggest purse in the history of the sport. As Tommy blazes a violent path toward the title prize, his brother Brendan (Joel Edgerton), a former MMA fighter unable to make ends meet as a public school teacher, returns to the amateur ring to provide for his family. Even though years have passed, recriminations and past betrayals keep Brendan bitterly estranged from both Tommy and his father. But when Brendan's unlikely rise as an underdog sets him on a collision course with Tommy, the two brothers must finally confront the forces that tore them apart, all the while waging the most intense winner-take-all battle of their lives.