Considering the praise for Victor Herbert’s score and leading lady Christie MacDonald, the relatively short run of Sweethearts is somewhat surprising. It ran four months on Broadway, enjoyed a post-Broadway national tour, was revived for a limited engagement in 1929, and was revived again in 1947 as a vehicle for Bobby Clark which ran for nine months. Everyone thinks they’ve seen the movie version with Jeanette MacDonald and Nelson Eddy, but the 1938 MGM musical was for all purposes an in-name-only adaptation that appropriated the show’s title and five of its songs but otherwise had a completely different plot.
Mikel Mikeloviz, disguised as a monk, transports Princess Jeanne, the infant daughter of King René of the little kingdom of Zilinia, to Bruges to wait in safety during the war. Dame Paula runs the Laundry of the White Geese and is known as Mother Goose. Mikel gives the princess to Paula in secret to raise as her own daughter under the name of Sylvia. Paula later has six daughters of her own who help her run the laundry. Their father has been at war for ten years.
22 years later, the people are demanding the restoration of a monarchy. Mikel is conspiring to restore Princess Jeanne to the throne, which is about to be offered to Prince Franz, the heir presumptive. Franz, while travelling in disguise, has fallen in love with Sylvia. But Sylvia, who does not know that she is really a princess, is bethrothed to Lieutenant Karl, a military lothario. A sleazy politician, disguised as Paula's battle-scarred husband, tries to ensnare one of the two apparently adopted daughters as the bride for Prince Franz, but he does not know whether the real adopted daughter is the scheming Liane or the sweet Sylvia. Mikel's plans are hindered by the schemes of three villains. Mikel also mistakes Liane, a milliner who has sought temporary employment in the Laundry of the White Geese, for the lost princess. After all the complications are combed out, Franz and Sylvia marry, vowing to rule together.