Beverly Ross, a switchboard operator at radio station KFEL, aspires to be a boogie-woogie playing disc jockey. One day, when one of the actresses on a dramatic show becomes ill, the director asks Beverly to fill in for her. This gives Beverly an idea, and when Vernon Lewis, the classical announcer of the early morning show, tells Beverly that he is not feeling well, Beverly urges him to take a vacation to recuperate and offers to substitute for him while he is gone. After Beverly takes over the early morning show, her brand of boogie invigorates the soldiers at a nearby army base. While driving to report to duty one day, recruits Barry Lang, a chocolate magnate, and his chauffeur, Andy Adams, hear the program and Barry bets Andy that Beverly is a shriveled-up old hag. In the barracks, Barry and Andy meet Beverly's brother Eddie, who slyly invites them home to settle their bet. When Andy accuses Barry of using his millions to impress women, Barry proposes that they switch identities, with Barry posing as a chauffeur and Andy masquerading as a millionaire. After Eddie is assigned to K.P. duty, Barry and Andy proceed to the Ross home alone and switch identities as planned. When Beverly confides her desire to have her own radio program, Barry suggests that she aim the show at the military troops throughout the country. Inspired by Barry's suggestion, Beverly names her show "Reveille with Beverly" and thanks Barry, who she thinks is Andy, for the idea. Later, after he hears Beverly blasting boogie in the wee morning hours, Mr. Kennedy, the head of the station, fires her, but when fan mail starts pouring in, he quickly rehires her. The vacationing Vernon, meanwhile, hears the broadcast and hurries back to the station to reclaim his show. Vernon's brother-in-law is a big sponsor at the station, and consequently, Kennedy is forced to give him back his time slot. Upon learning of Beverly's predicament, Barry arranges for his chocolate company to sponsor her show. Barry, who has become smitten by Beverly, is about to confess his deception to her when Andy arrives, and Beverly, still thinking that he is Barry, embraces him in gratitude. Soon after, Eddie comes home, and when he describes Andy and Barry, Beverly realizes that she has been fooled. Beverly then decides to broadcast her show from the army base, and Andy and Barry pretend to have the mumps to avoid attending. An officer discovers their ruse, however, and marches them onstage. When Beverly introduces Andy as Barry, the soldiers start to jeer and then straighten out the mix-up. Toward the end of the show, the troops are called to action, and as they march off to duty, Beverly broadcasts a personal message to Andy and Barry, forgiving them for their deception.