Bill Waters and Jerry Trainor are tent-mate draftees in the United States Army. Every night, Bill listens to a radio singer known simply as "The Lovely Lady of Song," waiting for her to end her show with her trademark sign-off, "Goodnight, Bill." The anonymous singer is Evelyn Loring Waters, Bill's wife, who is pregnant. The pregnancy is a secret, as Bill wishes to remain in the Army and Evelyn fears that she would lose her job if her condition was known. With the help of advertising executive Brad Saunders, Evelyn convinces her twin sister Patricia to take her job on the radio while she has her baby. Meanwhile, Jerry is released from the Army and he promises Bill he will look after his wife when he returns to civilian life and the radio business. Jerry arrives at the station, unaware that the real Evelyn is in a maternity home. Neither Patricia nor Brad are aware of Jerry's predicament, and they soon come to regard him as an idiot. Jerry continues in his solemn quest, trying to make Pat drink buttermilk or go to bed early. His persistence soon creates an intense rivalry between himself and Brad, for they also share responsiblities at the same advertising agency. Brad works to get Pat her own show, a new breakfast food program that his boss, Maxwellton, is trying to acquire. As hard as Brad works on Pat's behalf, however, Jerry works just as hard to slow her down, as he is worried that "Evelyn" is overworking herself. In an attempt to sabotage her audition, Jerry tells Pat that his boss loves the song "Annie Laurie." In actuality, Maxwellton hates it. Her chief rival for the job, nightclub singer Clementine, overhears their conversion, and as soon as she starts to sing the number, Maxwellton goes wild and ends the audition. Just as Jerry and Brad are about to exchange blows again, Evelyn goes into labor. Jerry rushes to the hospital, where he sees the twins together for the first time. In learning the truth, Jerry realizes that Pat is single and that he is in love with her. Jerry then jumps into action and convinces Maxwellton to hire Pat for the new show. With everything resolved, Jerry and Pat leave to get married.