A boxer likes a poor widow but goes nuts over a society lady who snubs him while he's trying to keep his face from being re-arranged fighting.
Pop (Guy Kibbee) sends his boxer Jim Kane (James Cagney) to the hot springs ranch for a rest. There he finds a nightclub singer Peggy (Marian Nixon) with her boy Dickie (Dickie Moore) needing treatment, who takes a photo of them kissing. Not getting life insurance money, Peggy needs $600 to stay. Kane gets a fight in Tijuana in which the winner will get $2,000 and the loser nothing. He gets beat up but wins and pays her bill. Peggy cries in gratitude. Kane wants to marry Peggy and goes back to fighting for Pop, winning seven bouts in a row.
Roger Elliott (John Roche) introduces Joan Gibson (Virginia Bruce) to Kane. He drinks milk at the Stork Club, putting down "Jap fighters" and saying he could win the war. Kane takes Joan home, but she closes the door on him. Peggy gets a brief postcard from Kane and makes up more for her son. In high society Kane thinks the Russian 5-year plan means installment bills. He asks Joan for a tumble, but she says his face is blemished. Pop gets Kane a title fight, but he rejects it. Instead Kane gets plastic surgery on his nose and takes lessons on being a gentleman. He calls on Joan and shows her his new face, kissing her. He's ready to stay the night; but her friend Ann (Esther Howard) comes in, talks about her divorce, and stays all night. He complains and leaves. Joan tells Ann she can have Kane.
Kane tells Pop to get him an easier fight, and Kane is satirized on the sports page for his make-over. He dances in a fight to protect his face and loses. Peggy arrives and says Pop sent for her. Kane puts her off until morning and goes to ask Joan why she walked out of the fight. He tells her to watch him beat Al West; then he'll retire, and they can get married. Peggy makes breakfast for Kane, then realizes he met someone else. Kane gives her money; she tells him to get out and throws the money at him.
Kane fights West for the championship, but Joan's seat is empty. Kane learns she is sailing for Havana in twenty minutes. So he slugs it out with West to win soon and takes a taxi to the pier. Joan and Roger board the ship. Kane runs aboard and finds Joan. When Roger comes in, Kane hits him and kicks Joan. With his broken nose Kane tells Peggy he's crazy about her and gives her a hot ring. In the final shot they kiss.
Kane learns that he was just a temporary diversion for Joan, as boxing is for fans. His face and brain are damaged fighting, and becoming a gentleman takes more than a few lessons. Yet he realizes that he and Peggy have a real friendship and can care for each other.