Southpaw Billy “The Great” Hope (Jake Gyllenhaal), is a professional boxer who fights in Light Heavyweight with an Orthodox position, and an impressive record of 42W0L0D. He is a resident of New York City together with Maureen McAdams and their one daughter Leila (Oona Lawrence). In his fight against Darius Jones (Cedric D. Jones) at Madison Square Garden, Maureen is scared as Billy is hit with a number of devastating blows on the face that result in massive bleeding out of his eye. Although he suffers from severe injury, Billy wins the match with a knockout. He’s still the owner of the title of light heavyweight.
The media has been focusing on Billy an aspiring boxer who is a rising star, Miguel “Magic” Escobar ( Miguel Gomez) is warning Billy to take on the Mexican. Maureen is worried about Billy’s safety once the boxer is back home and she urges Billy to give up. Then, Maureen speaks to Jordan Mains ( 50 Cent) the manager of Billy. She is against Mains’ plan to sign Billy to a two-year contract for three bouts.
Billy and Maureen attend a fundraiser ball that Billy gives a speech to thank Maureen and Leila and Jordan and his fellow guests. Miguel is also present, and as Billy is about to leave, Miguel goads him by calling him as a deceiver Maureen and threatens to to take her title from him, resulting in a brawl. The sound of shooting (from Miguel’s brother Hector) is heard and Billy discovers that Maureen is dead. Hector runs away from the scene, but Maureen is alive in Billy’s arms.
Billy starts to consume alcohol and other drugs. Jordan suggests that he sell his home to help him solve his financial troubles. Jordan then invites Billy to fight Kalil Tray. Billy is so beat that his team quits. In the dark after a headshot, Billy falls and hits the ref’s face. Billy is suspended for one year and isn’t making any money because he’s accountable to the referee and the network damages. His house and possessions are confiscated. Both Jordan and his long-time trainer Eli Frost abandon him to collaborate with Miguel.
One night, Billy drove his car into a tree in the vicinity of his home. Leila realizes that Billy is bleeding to the ground and calls 911. Leila Rivera, Naomie Hari is the Child Protective Services Officer who wakes Billy up on the floor. Billy is forced to visit the Wills Gym, where he is introduced to Tick Wills ( Forest Whitaker), an ex-boxer who is blind in one eye after the last bout he fought. Tick wants to help Billy get back on his feet. Tick is aware of his addiction to drugs and is willing the opportunity to coach him.
Angela and Billy meet for a visit with Leila. Leila accuses him of being a victim of their differences and refuses Leila to visit him. Billy goes back to the gym and accepts the janitorial position. While working out Billy makes friends with a kid named Hoppy ( Skylan Brooks) who is also aspiring to be a boxer. He finds out Hoppy’s father abused his mother, and this is reported to Tick. He starts to make amends within his own family and attends to Leila. His persistence will win him over. After winning a charity match, Billy is visited by Jordan. Miguel the winner from Kalil Turay is the manager of his. Jordan is keen to schedule a fight between them in the next six weeks, as he is convinced that Billy will not have time to practice. Billy thinks he can make his comeback and would like Tick to be his coach, but Tick does not want to, believing that Billy is merely seeking revenge.
Billy later discovers from Tick that Hoppy was killed while trying to save his mother from the father who killed his father. Tick regrets that he didn’t get to save Hoppy and proposes that he aid Billy prepare for the fight. Noting his efforts to change things in his life The judge allows Billy custody of Leila and she returns into his. While visiting Maureen’s grave Billy tells Leila that he’ll be fighting once more and she accepts his request to allow her to remain in the current.
Angela takes Leila into her dressing area during the fight. Angela brings Leila to her dressing area throughout the fight. He turns his back and, following an uncontrollable uppercut, he knocks Miguel to the canvas. Miguel stands up in the last second, and the corners are packed with the staffs of two teams.
Despite a split vote , which awarded the first round to Miguel, Billy is announced as the winner. After a short silence, Billy is able to collapse and thank Maureen before giving his life over to Leila. Tick and his team members place him on their shoulders, before he closes his eyes and smiles. Leila and Billy sit in the dressing room after the fight. They hugged for the first times since Maureen’s death. She tells Billy that Maureen would be proud of her and she tells him she loves him.