Joe and Jerry, two musicians down on their luck while wandering through Chicago, by chance witness a gang rub-out in the Clark Street Garage. The rub-out was ordered by Spats Palazzo, a notorious Chicago hood. Spats and his boys immediately chase after Joe and Jerry, determined to silence them as witnesses to the crime. Desperate for a quick way out of town, Joe and Jerry hear about jobs available for a saxophone and a bass player, which are their specialties. And coincidentally, the band is scheduled to leave at once for Florida. There is only one problem; the band is all female. As Joe and Jerry they haven't got a chance, but with a bit of costuming, padding, makeup and slight voice adjustments, they become Josephine and Daphne. They are hired by "Sweet Sue and her Society Syncopators."
Joe (Josephine) and Jerry (Daphne) find themselves getting well acquainted with Sugar, the gorgeous blonde who is the featured singer with the band. As difficult as it is for them not to reveal their secret to Sugar, they know that one slip could lead Spats Palazzo to them. Moreover, if Mr. Bienstock, the show's manager, discovers their true identities, they could be in an even worse spot. Mr. Bienstock had already warned the "girls" that he would not tolerate drinking or men on the train between shows. Joe and Jerry are definitely in a jam, but it looks as though Sugar's company is going to make it an enjoyable, if risky, experience.
It turns out that Sugar has a drinking problem, which she keeps secret from Mr. Bienstock. As she explains it, she drinks to forget about the countless saxophone players she has fallen in love with, and who have left her. This is quite interesting to Josephine, whose interest in Sugar is becoming more than sisterly.
Sugar confides to Josephine and Daphne that she plans to find a millionaire in Florida and get married. She even tells them what he will look like. Hearing this, Joe develops a plan; he convinces Jerry that they need to look after Sugar, so they need to stay with the band in Florida until they find a suitable millionaire for her. What Jerry does not know is that Joe has already chosen Sugar's match. By disguising himself as her "dream-man," Joe is confident that he can win her heart. After she falls in love with him, he plans to tell her the truth about himself.
While Joe is busy impressing Sugar with his newfound wealth, Jerry (alias Daphne) has attracted her own millionaire. Sir Osgood Fielding is determined to woo and win Daphne. She is not quite certain how to break the bad news to him, especially since he showers her with lavish gifts.
With the unwitting help of Sir Osgood, Joe makes a big impression on Sugar. Now Joe only needs to tell her the truth about his identity, since he thinks that if she really loves him it won't matter that he is not a millionaire, but another saxophone player. Unfortunately, before he gets the opportunity to tell her, Spats Palazzo and his gang arrive in town and recognize Josephine and Daphne in the band. The chase is on. Eventually the villains get what they deserve, and the lovers are reunited.