The play's first act finds three young couples (Sam + Jo hosting Fred + Carol and Lucinda + Edgar) engaging in party games like Twenty Questions. Jo's angry bitterness becomes apparent earlier than its source, which is the terminal disease that tortures her and will soon claim her life. At the end of the act, after the mounting tension drives the guests to leave, Sam carries Jo up to bed. Suddenly, a fourth couple appears from the wings: a glamorous older woman (Elizabeth) and her black companion (Oscar). She asks the audience, "Are we in time? Is this the place?" and answers her own questions: "Yes, we are in time. This is the place." The curtain falls.
In Act One, the recurrent theme of the game was "Who are you?" Now that question becomes more serious, as Sam, shocked by the appearance of these strangers in his house, repeatedly demands that Elizabeth reveal her identity. She eventually insists that she is Jo's mother, come from Dubuque, Iowa "for her daughter's dying". However, Sam knows Jo's mother as a small, balding woman with pink hair, who lives in New Jersey and is estranged from Jo, and Elizabeth is clearly not she. Unfortunately for Sam, who vigorously protests the veracity of Elizabeth's claims, Jo runs into Elizabeth's arms and never questions her appearance or identity. Whoever she and Oscar may—or may not—be, they clearly represent the coming of Death, something familiar and unknown. At the end of the play, Oscar carries the dying Jo upstairs one last time. As the devastated Sam demands once more to learn Elizabeth's true identity, she ends the play with this line: "Why, I'm the lady from Dubuque. I thought you knew. [to the audience] I thought he knew."
Elizabeth's curtain lines, quoted above, both typify the Pirandellian style of the play's dialogue, in which characters frequently make comments directly to the audience. (The first occurs very early, when Jo, observing the Twenty Questions game in progress, looks out at the audience and asks, "Don't you hate party games?")