Having suffered several defeats in a row, the promising heavyweight boxer Jim Braddock is forced to quit the sport. During the Great Depression, Braddock takes up any work to feed his wife May and children. However, he still hopes to return to the ring. And once he is given the chance. At the last minute he replaces another boxer to fight with a contender for the world title. To everyone's amazement, Braddock wins in the third round. Despite the fact that he weighs less than his rivals and also suffers from numerous injuries, Jim continues to fight and to win. Apotheosis of his athletic career becomes a duel with world champion Max Baer, who killed two people on the ring.