A melancholic
U.S. Marine Thomas "Tommy" Riordan visits his father, Paddy Conlon, a recovering alcoholic who has returned to his Roman Catholic faith in
Pittsburgh, Pennsylvania. As a child, Tommy had to run away from Paddy with his dying mother due to Paddy's being an abusive alcoholic and has never forgiven him. Paddy tries to convince him that he has changed, but to no avail. The next day, Tommy enters a gym where he quickly knocks out Pete "Mad Dog" Grimes, one of the world's best middleweight fighters; a video of the fight goes
viral on the Internet. Learning about a winner-takes-all
mixed martial arts tournament called Sparta, whose winner will receive $5 million, Tommy asks Paddy to help him train for the tournament, but only under the condition that Paddy does not try to repair their relationship. Tommy pledges to win and then donate the entire $5 million purse to Pilar, the widow of Manny, one of his friends in the corps. Tommy's older brother Brendan, a high school physics teacher and former MMA fighter, is struggling to provide for his wife, Tess, and their two daughters. He had to mortgage his house in
Philadelphia to pay for his younger daughter's
open heart surgery and is now in danger of losing it. To increase his income, Brendan starts battling amateur fighters for money. He is suspended without pay after details of his secret life spread around the school. Paddy meets Brendan in his driveway to try to reconcile with him, albeit unsuccessfully, and to tell him that Tommy is back in town. Brendan seeks the training of old friend Frank Campana and begins competing in smaller venue fights. After the fighter Frank planned to enter into the Sparta tournament is injured, Brendan convinces Frank to enter him as a replacement. When the brothers separately enter the tournament, it is revealed that Tommy is angry at Brendan for bailing out on him and instead staying behind for Tess when Tommy and their mother left Paddy; Tommy was left to care for their mother when she became
terminally ill. Brendan claims that he was helplessly in love with Tess and that he has forgiven his father for the wrong he has done, but Tommy is unconvinced and walks away. Meanwhile, the video of Tommy beating Grimes attracts the attention of a Marine, who tells the press that Tommy saved his life in Iraq, by ripping off the back hatch of a drowning tank. Although Tommy becomes a national hero, his military records reveal that he
deserted after everyone else in his unit was killed in a
friendly fire bombing. He reveals his plan for his winnings. The military police will take him into custody but will wait until after the tournament is over. Over two fights, Brendan and Tommy have contrasting fortunes: Tommy quickly and brutally
knocks out opponents, all while barely speaking, while Brendan is outmatched physically but uses
Brazilian Jiu-Jitsu to force
grappling submissions. The night before the final day, Paddy attempts to talk to Tommy about his actions in Iraq. Tommy angrily dismisses his father, letting out all his pent-up emotions. As a result, Paddy relapses and starts drinking again. Seeing his father in pain, Tommy calms and comforts him, thus resurrecting their relationship. In the semifinals, Tommy is matched up with Mad Dog Grimes; beating him into submission after a fierce struggle, and the commentators claim this is one of the fastest knockouts in MMA history. Brendan is matched up with undefeated Russian wrestler Koba, who dominates him in two rounds. In round three, Brendan swings for the fences, making the bout a back-and-forth battle. In the closing moments of the final round, Koba takes Brendan's back from the
clinch, and Brendan goes for a rolling
kneebar. As Koba attempts to escape the position, Brendan quickly reverses and readjusts the kneebar, narrowly winning by submission. Tommy and Brendan's relationship is revealed to the world when they are the tournament's last remaining fighters. Brendan shows desire to reconcile, but Tommy, still in pain, shows no interest in doing so. Tommy wins the first two rounds, but Brendan eventually dislocates Tommy's shoulder with an
omoplata arm-lock. Brendan wants to tell the referee about Tommy's dislocated shoulder and end the fight, but his coach suggests otherwise. As the fourth round starts, Brendan insists Tommy give up as Tommy only has use of one arm. Tommy continues to fight. Brendan unloads a barrage of strikes trying to win. Tommy asks Brendan to continue hitting him as the fourth round ends. At the start of Round 5, Brendan realizes he has to force Tommy to submit, and he traps him in a
rear-naked choke. As they struggle on the canvas, Brendan apologizes to Tommy and tells him that he loves him. Tommy submits after hearing the words. Brendan and Campana tactfully avoid the referees and the doctors checking in on Tommy. The reconciled brothers exit the ring as their father walks away into the background smiling. ==Cast==