Agnes and Tobias, an affluent elderly couple married for about forty years, sip after-dinner drinks in their living room one autumnal Friday evening. They chat pleasantly about Agnes’s persistent belief that she might one day easily go mad. Agnes’s younger sister Claire comes down from her room to apologize for an embarrassing incident she caused during dinner and is severely rebuked by Agnes for her drunkenness. Agnes then goes to telephone her daughter Julia, who lives some distance away. Left alone with Claire, Tobias inquires about her previous experiences with Alcoholics Anonymous. She explains that she felt alienated at those meetings and, after relating a bitter anecdote about herself, insisted that she was not an alcoholic because she drank willfully. Agnes returns, informing them that Julia is leaving her husband and will come home immediately. She reproaches Tobias for failing to admonish his daughter appropriately following her three previous divorces, and he responds by telling a story about a cat he once owned that stopped liking him for no apparent reason; when his efforts to regain his pet’s affection failed, he had it euthanized.

While Agnes and Claire comfort him, unexpected guests arrive. Harry and Edna, close friends for forty years, felt uneasy and distressed at home alone. Pressed to explain, they relate that after dinner they suddenly became strangely frightened, for no particular reason. They could no longer endure remaining alone in their house. Agnes offers them Julia’s room for the night, and they retire. Claire suggests that she knows exactly what happened.

Saturday evening before dinner, Agnes tries to calm Julia, who is angry about the intruders who remained locked in her former bedroom all day. Agnes casually describes a psychoanalytical study she is reading about the reversal of sex roles in American society. Feigning the attitude of a father when Tobias enters, Agnes leaves Julia to be counseled by Tobias. Father and daughter merely quibble and argue about her three previous marriages until Claire interrupts them to tell about her unsuccessful attempt to buy a topless bathing suit at a local department store. An antagonistic conversation ensues among the three. It continues until Agnes joins them for cocktails and reports that Harry and Edna earlier requested sandwiches to be brought to their room. Julia explains that she left her husband because of his insupportable negative attitudes. Harry and Edna come down, announcing that they are going home to get their things and will return after dinner.

Julia upbraids her mother for prohibiting any discussion of serious matters during dinner. Agnes claims merely to have been keeping the family “in shape” on uneven ground by maintaining a reasonable balance among all the elements. Claire comes in with an accordion but is persuaded not to play it. After the sisters exchange sarcastic remarks concerning their sexual histories, they all discuss whether to permit the unwelcome guests to remain any longer. While Agnes and Tobias greet their returning friends, Claire and Julia discuss this awkward situation. When Edna enters the room, Julia expresses her hostility quite openly, but Edna insists that she has some rights. Julia then blocks access to the sideboard, preventing Harry from mixing drinks. Growing hysterical at the persistence of their demands, she runs screaming from the room. Tobias returns and is giving an account of Julia’s continuing fit of hysteria upstairs when Julia enters with a pistol and orders her father to expel the unwanted guests immediately. Tobias disarms her, and, while Edna is explaining that long-term friendship gives them the right to live there, Agnes leads her daughter up to bed. Harry and Edna retire,...