Jimmy Kane, a carnival high diver, owes his success to the encouragement given him by his assistant, Betty Roberts, who always screams "Okay, big boy!" before his dives. When Jimmy and Betty witness a wedding celebration in a restaurant, they decide to marry also. After the carnival closes, Jimmy, who vows to go to Broadway and make "the big time or bust," fails to land a job there, and they face hard times until an old friend gets Betty a small part in a nightclub show. When John Hammond, a suave playboy, sees Betty, he takes an interest in her and gets her an audition with a big producer. Betty becomes a star on Broadway, while Jimmy's pride is hurt because she is supporting him. Although Betty refuses Hammond's advances, he falls in love with her and gives her an inscribed bracelet. Already humiliated by Hammond's attentions to his wife and the gossip about the two of them, Jimmy believes he has lost her when he sees the bracelet. He leaves town, gets another assistant and resumes his act, only to discover that he has lost his nerve. Jimmy decides to kill himself by missing the tank in his dive, but on the platform, he hears the call, "Okay, big boy!" and sees Betty, who has learned the reason he left, and given up her career for him. Jimmy makes a spectacular dive and they are reunited.