Marshovia, a small European kingdom, is on the brink of bankruptcy but the country may be saved if the wealthy American Crystal Radek, widow of a Marshovian, can be convinced to part with her money and marry the king's nephew count Danilo. Arriving to Marshovia on a visit, Crystal Radek change places with her secretary Kitty. Following them to Paris, Danilo has a hard time wooing the woman he believes is the widow after falling in love with an attractive young woman at a nightclub, the same Crystal Radek who presents herself as Fifi the chorus girl.