In his mid-20s, Ali (Matthias Schoenaerts](/actor/matthias-schoenaerts)), an unemployed single father, moves to Antibes, southern France, with hopes of finding work to support his young son, Sam (Armand Verdure). Lacking financial resources, he stays with his sister Anna (Corinne Masiero), who herself is struggling with her own economic issues and transient jobs.
Ali secures a job as a bouncer at a nightclub but harbors a burning desire for kickboxing. One evening, he encounters Stéphanie (Marion Cotillard) and offers to help her home after she is injured in a brawl at the club. Stéphanie works at a marine tourist park, where she suffers a life-altering accident during a performance, waking up in the hospital to discover her legs have been amputated.
While on the job, a colleague informs Ali about a kickboxing event that presents a money-making opportunity. Meanwhile, Stéphanie's new life in a wheelchair leaves her engulfed in despair, prompting her to reach out to Ali. He responds by taking her to the beach, where they share a refreshing swim.
As time passes, Ali and Stéphanie develop a strong bond, often engaging in casual sexual encounters, while Ali remains forthcoming about his other relationships. Stéphanie begins attending Ali's kickboxing matches, and a symbiotic relationship forms between them. With Ali's support, Stéphanie regains her confidence, acquires prosthetic legs, and learns to walk again. She even starts managing Ali's betting for the kickboxing matches.
Their journey takes a turn when Ali and Stéphanie visit the nightclub again, where Ali flirts with a girl while Stéphanie watches, leading to feelings of jealousy. Meanwhile, Anna loses her job due to management's discovery of her actions related to expired food, placing the blame on Ali for his inappropriate job installing hidden cameras at work. This escalates into a confrontation between Ali and Anna's partner, forcing Ali to leave.
While Sam spends time with Anna, Ali goes to a remote kickboxing training facility, causing distance between him and Stéphanie. During a visit from Sam, a tragedy unfolds when Sam falls through a weak spot in the frozen lake. Ali, upon realizing Sam is missing, desperately breaks through the ice to rescue him, injuring his hands in the process but ultimately saving his son.
In the hospital, overwhelmed with emotion, Ali confesses his love for Stéphanie during a heartfelt phone call, recognizing his past insensitivity. As the story concludes, we see Ali turning professional in the kickboxing world, supported by Sam and Stéphanie, who stand by him in what appears to be a post-fight victory celebration.
