Shortly after sports promoter Trego buys boxer Johnny Rocket's contract, he learns that Johnny plans to quit the ring after his next fight at the request of his fiancée, Angela Grinnelli. Trego is convinced that Johnny has what it takes to become a champion and when he cannot induce Johnny to change his mind, Trego makes sure that he is unable to find another job. Johnny and Angela marry, and when Angela becomes pregnant, Johnny asks Trego to take him back. One day while Johnny trains, Gloria Van Ness, the daughter of a newspaper publisher and an aspiring sports writer, comes by the gym. Trego introduces her to Johnny, whom he presents as the next big fighter. Gloria is interested in Johnny romantically, but devoted to Angela, he spurns her advances. One night, while Johnny is in the ring, Angela gives birth and the baby dies shortly afterward. Johnny feels guilty, but soon becomes even more dedicated to winning the championship. Before long, Johnny's head is turned by Gloria's interest and Angela leaves him. Then, convinced that he is undefeatable, Johnny fires Trego. In revenge, Trego gives Johnny a drugged mouthpiece and he loses his fight. Because Johnny's poor performance made it appear that he intentionally threw the fight, he is suspended from boxing. Now that he is no longer famous, Gloria drops Johnny, and using an assumed name, Johnny starts fighting in small towns. Eventually he suffers a concussion and is warned that he must never fight again. When Johnny learns that Angela paid his hospital bills, he attempts to see her, but is sent away by Angela's father. Feeling hopeless, Johnny enters another match. When Angela learns this, she rushes to the ring to stop him, but is too late. Johnny is not badly hurt, however, and now reunited, he and Angela leave for the country, where Johnny has gotten a job on a health farm.