Frank, a dedicated schoolteacher, embraces the sexual freedoms of the city’s underground scene—navigating a double life in public restrooms, cinemas, and cruising spots. When he meets Bernd, a sweet and steady museum worker, he finds himself torn between the comfort of domestic partnership and the allure of anonymous desire.

Frank and his S&M partner are surprised by Frank's harridan mother when she walks in on the pair in an amorous clinch. Frank's mother threatens to disinherit her son if he does not settle down and get married. Frank hires the actress Klara to pose as his wife, and the pair moves into a quaint country house. Soon the newly weirds are both after their handsome neighbour Eugen. Frank becomes confused when he feels he may be falling for his first female.