Frances is a pretty innocent young woman who gets a handbag in a subway car in New York City and decides to return it to her owner, with the information that was added to the bag with a note from the address. Its owner is Greta, a piano teacher who loves classical music. As a Frenchman has just lost his mother, he becomes very close to Greta quickly. This friendship is gradually becoming strange and obsessive; Frances begins to realize in the end that nothing is as it seems in Greta's life.