The first shot is of a herd of sheep grazing peacefully on the island where Andreas Winkelman, introduced by a voice-over by Bergman, is working on the roof of his house. Anna Fromm stops by to use the telephone. At this point the action is interrupted for the first of a series of interviews with the actors. He asks Max von Sydow to interpret his role as Winkelman.

Anna leaves her handbag behind and Andreas finds a letter in it written by Anna's husband, also called Andreas, speaking of the inevitable dissolution of their marriage. Andreas finds a puppy hanging in a tree, the first of a series of sadistic acts on the island. The perpetrator is never found but a poor old bachelor, Johan Andersson is blamed by the islanders.

Anna is staying with Winkelman's neighbours, Elis and Eva Vergerus. During an overnight visit, Andreas gets to know the Vergerus'. Elis is an architect but his hobby is portrait photography. He collects pictures of people taken off-guard, which he files under different categories. He adds Andreas to his collection making him reveal his past, which includes check forgery, drunk driving and police assault.

At another Vergerus dinner Anna talks of her unhappy marriage but no one believes her. At night she is plagued by nightmares. Interviewed by Bergman, Liv Ulmann describes Anna as a fanatical truth seeker but also as a person who fabricates reality when people around her do not respond to her. During one of her husband's business trips, Eva stays with Andreas and tells him about Anna's past; her husband and son were killed and Anna hurt in a car accident. In her analysis of Anna, Bibi Andersson sees her as suicidal but believes she will survive the present crisis with a new sense of worth.

Anna and Andreas move in together. Violence creeps into their life. A bird flies against the window and is killed. They watch the execution of a soldier in Vietnam on TV. On the island there are more reports of animals being killed and the hunt for Johan intensifies. Their relationship deteriorates and Andreas attacks Anna physically.

A fire has been started at a barn and a horse burned alive inside. Anna picks Andreas up at the barn and in the car on the way back he asks to be free, accusing her of telling lies. He reveals he has read her letters in her bag. Anna seems to lose control of the car and Andreas grabs the wheel accusing her of trying to kill him as she did her former husband. Anna replies she has come to ask for forgiveness. His feelings are ambivalent towards her and outside of the car does not know what action to take. He sinks down on the road and the camera pans away until he is just a speck on the landscape. Bergman's voices declares: This time his name was Andreas Winkelman.