"Slim" Swasey, ironically nicknamed because of his girth, is Rome, Missouri's jack-of-all-trades, working as porter and desk clerk at the local hotel and as self-appointed guardian to Sally Jo, known as "Tinkle," a young girl abandoned by her show business mother. Slim loves Ollie Remus, daughter of banker Jasper Remus, but she has suddenly fallen for "Sure Thing" Sherman, a slick newcomer in Rome. Masquerading as an evangelist, Sherman and sidekick Isadore Kelly have arrived during the county fair, intending to rob Jasper's bank while fellow conspirator Madame Le Grande keeps everyone gazing skyward as she performs her air balloon stunt. Sally Jo discovers that Madame Le Grande is her mother, and learns of the conspiracy. She alerts the rotund Slim Swasey, and he rescues her after she hides inside the balloon gondola and is swept into the air as it breaks its moorings. Slim exposes the criminals, beats up Sherman in the church belfry, returns the stolen money, and wins the love of Ollie Remus, who realizes he saved her from eloping with a miscreant.