Transient workers are pouring into Sleepy Lagoon by the thousands to work in the local defense factories, with no means of finding good clean fun in a town that has been as moribund as its name for years past. They have been squandering their earnings and going into debt at the gambling houses, hostesses-provided dance halls, and saloons that have opened up overnight. Judy Joyner, a young radio personality whose voice is heard nightly over the local radio station, is put up as mayoral candidate on an all-female reform ticket backed by suffragist Sarah Rogers, and wins the election easily against the shady politicians headed by pork-barreling Mayor Cyrus Coates. Mrs. Crumm is chosen by Judy to be the new chief-of-police. Judy thinks re-opening the derelict old amusement park down by the shore will serve as the amusement place needed to solve the problems, and sends for her Uncle Dudley, a carnival man from way back, to be the manager. But Jay Lucarne, alias The Brain, the gambling racketeer for whom Dudley stooges for a living, sees the Sleepy Lagoon set-up as a foolproof dish of gravy into which he can dip his fingers with full official protection of the lady-mayor--unknown to her. He forces Dudley, with a gun in his back and threats against his niece, to accept the job, and The Brain and his gang of thugs move in on Sleepy Lagoon. Before long, a flourishing gambling hall is being run in a subterranean hall beneath the park--and Judy is facing charges of political corruption.