Jim Braddock - a heavyweight in boxing, he showed great promise in the sport, but the last fights he was not lucky, and he lost several times in a row. The Great Depression comes, and in order to feed the family, Braddock agrees to any income. But do not lose hope to return to the boxing arena. Soon he was lucky. A few minutes before the fight, he stands in place of another fighter against the contender for the title of world champion. Surprisingly, Braddock knocks out for three rounds. Despite the advantage of rivals in weight and a large number of injuries, Jim successfully wins the fight for the fight. The culmination will be a fight with the reigning champion, who killed two people during fights.