In Vienna in the early twentieth century, Lisa (Joan Fontaine), a teenager living in an apartment building, becomes fascinated by a new tenant, concert pianist Stefan Brand (Louis Jourdan). Stefan is making a name for himself through energetic performances. Lisa becomes obsessed with Stefan, staying up late to listen to him play, and sneaking into his apartment and admiring him from a distance. Despite her actions, they only meet once and Stefan takes little notice of her.