Crickets, a timorous former acrobat and comedian, works as waiter in Ma Brennan's restaurant, where Mary, the owner's stage-struck daughter, is in love with Jimmy Moore, a saxophonist. Sam Platz, a theatrical press agent, recognizes Crickets as an old acquaintance and promises to promote Mary's career. At the same time, Two-Gun Terry, a neighborhood gangster, kills the leader of the Hudson Dusters, a rival gang, and the leaderless gang takes refuge in the restaurant, followed by Terry; terrified, Crickets tries to serve him and accidentally knocks him unconscious; hailed as a hero, he is elected to head the Dusters and is assigned to force a manager to give Mary a chance on the stage. He succeeds in getting her the job of understudy in George White's Scandals by locking the star in her apartment. Mary sings the role and is hailed by the critics though rebuffed by Jimmy; but Crickets effects their reconciliation after she has risen to stardom, giving them his patented mosquito exterminator for a wedding present.