A radio announcer discovers that one of his colleagues is working with the mob.

William J. Brennan, who works in a music shop, aspires to become a radio announcer, but when Smedley, his employer, finds him practicing with a dummy microphone during working hours, he hurries William out to wait on Marion Ferguson, a customer with whom William flirts and whom he pursues into the street. After being fired, he follows Marion to a radio broadcasting studio, where he meets Sam Ferguson, his old friend and Marion's brother, and volunteers to help him revive the waning life of the station. In addition to attracting many performers, an advertisement brings Dr. Kruger, leader of the Ghost Gang, who plans to direct the activities of his gangsters by broadcasting instructions under the guise of a clairvoyant mystic. William interferes in his plans, and Kruger orders him kidnaped and plots to have him eliminated during a bank robbery; but William contrives a scheme for tipping off the police and his friends by using newspaper headlines, and he is rescued in a final hectic chase.