After having suffered several defeats, a promising heavyweight boxer Jim Braddock is forced to quit boxing. During the Great Depression, Braddock takes any job to support his wife Mae and children. Thus he still hopes he will return to the ring, and one day he is given such a chance. At the last minute, he replaces another boxer and enters a fight with a contender to the title. To everyone’s surprise, Braddock defeats his rival in the third round. Despite his lighter weight and multiple injuries, Jim continues fighting and wins. In the end, he will confront Max Baer, the world champion who killed two people in the ring…