Understanding this enigmatic psychological drama requires a climb of "the Mount Everest of cinematic analysis", as some critics have put it. In Persona, Bergman explores the concepts of insanity, duality, and personal identity, possibly based on Jung's theories, and links them to themes as filmmaking, homosexuality, abortion, and motherhood, capturing all an experimental form. While writing the story, Bergman had two actresses in mind for the lead roles: Bibi Andersson and Liv Ullmann. Eventually, they actually played the parts.
Alma (Andersson), a young nurse, is charged with caring for Elisabet Vogler (Ullmann), a stage actress who suddenly has stopped speaking and moving. They stay in a clinic first, later moving to a summer cottage by the sea. As they spend time together, Alma speaks to Elisabeth constantly, telling her that she is the first person ever to listen to her. When Alma discovers that Elisabet has been passing on some of the intimate stories she has shared, tempers flare. At the same time, their identities begin to merge.