Christl's aunt urges her to marry Dr. Heider. Although she hardly knows him, Christl accepts - mainly to escape her overprotective aunt. But since she doesn't want to live with her new husband, she switches roles with her self-assured twin sister Annelie, who promises to get rid of him in just a week. Meanwhile Christl substitutes her in her job as secretary of a componist. Of course both get into their roles and start to like their exchanged men...