Four years after forfeiting a major fight, Jackie Justice lives with her boyfriend and manager, Desi in the heart of inner-city Newark, earning a living as a housecleaner. She relies on alcohol to cope with the tedium of her daily life. Desi pushes Jackie to start fighting again, but she refuses, angrily blaming him for mismanaging her career.
Desi takes Jackie to an illegal underground match, hoping to sign a new fighter. The crowd roars as the mysterious “Werewolf” provokes her into stepping back into the arena. When Jackie finally loses her temper, she pins the Werewolf down and headbutts her unconscious. That explosive moment catches the eye of Immaculate, a local promoter behind Invicta Fighting Championships, who recruits Jackie and sets her up with trainers, including Buddhakan and Pops, to rebuild her fighting shape and focus.
Heading home, Jackie and Desi are pulled over by her estranged mother, Angel McQueen, who has Manny Lyons Jr. with her. Manny, Jackie's six-year-old son, has not spoken since a traumatic incident in his infancy, and his custody shifts after his father was killed in a shooting. Manny moves in with his mother, and Jackie, under the guidance of Buddhakan, slowly gets back in shape. Immaculate convinces her to sign a contract with him that excludes a manager, a move that infuriates Desi, yet they eventually patch things up. As Jackie grows closer to Buddhakan, she discovers that she is also a mother who has not seen her child in more than two years due to the collapse of her marriage.
Jackie enrolls Manny in school and begins to learn how to be a mother, even dumping all of her alcohol down the sink. However, her relationship with Desi deteriorates, until he snaps, smashing Manny’s keyboard and hitting Jackie in the face when she tries to intervene. Jackie leaves him for good with Manny, and Angel reluctantly allows them to move in with her until the upcoming fight.
Jackie is pitted against Lucia Chavez, Invicta FC’s flyweight champion, in an Atlantic City title bout. Immaculate claims the fight is a path back into the UFC, but he later admits he recruited Jackie as a mere can against Chavez. Jackie endures a panic attack, reliving the memory of her last fight, and Manny tries to comfort her, until she screams at him to go away. He runs off, and a stranger brings Manny to Angel, who rebukes Jackie, telling her she is an unfit mother.
With no one else to turn to, Jackie starts living with Buddhakan, throwing herself into training. The bond deepens as they share fears and moments of vulnerability, and they kiss and become intimate. Yet when Buddhakan asks her to consider making their relationship official, Jackie admits she is not ready, and Buddhakan goes on a bender, ending up hospitalized the day before the fight.
With only Pops in her corner, Jackie enters the fight against Chavez distracted, so the champion dominates the first round. In the second and third rounds, Jackie finds her footing, wearing Chavez down and winning over the audience. In the fifth and final round, Jackie matches Chavez blow-for-blow, ending in a split decision, where Chavez narrowly retains her championship. Despite the result, the crowd and Jackie celebrate a remarkable comeback.
After reconciling with Buddhakan, Jackie returns to Angel’s, promising they’ll get their own place. As they walk down the street, Jackie pauses to help Manny tie his shoes, and he speaks to her for the first time, recognizing her as his mother.
