The play takes place in Ballybeg, Ireland, on the night before Gar's departure for Philadelphia. He is going to live with his Aunt Lizzy and Uncle Con. Lizzy is the sister of Gar's late mother, Maire, whom he never knew. Throughout the play, we see two versions of Gar portrayed by separate actors; one is his Public Self and the other his Private Self.
Gar is jubilant about his departure and teases his maid, Madge, about all of the fun he's going to have in America. He is disappointed that his father, S.B., a shop owner and Gar's boss, has not even mentioned his departure, instead acting as though everything is business as usual. In his conversations with Madge and Private Gar, Public Gar expresses his deep disappointment in his father's inexpressive and tight-lipped temperament.
In his bedroom, Private and Public Gar think about Gar's lost relationship with a local girl, Kate, and we see a flashback of them together on a date, planning to get married. In the flashback, Gar goes to ask Kate's father, a senator, for Kate's hand, but when he finds out that Kate has a more professionally ambitious suitor, he backs out and leaves. Gar remembers the event with great remorse, as Madge calls him in for tea.
While Public drinks tea with his father S.B., Private makes fun of S.B. They are interrupted by Gar's former schoolteacher, Master Boyle, a drunken but well-meaning man who gives Gar a book of poetry and tells him not to look back when he gets to America. At the end of his visit, Boyle asks Gar for some money for liquor and hugs him, giving him the moment of emotional connection that S.B. can't.
In a flashback, we see Aunt Lizzy convincing Gar to come to America. After this flashback, Gar's friends, Ned, Tom, and Joe all come to visit him, but are unable to say anything substantive about his leaving. At the end of their visit, Gar learns that they only came over because Madge invited them. This angers him and only makes him want to move to Philadelphia more.
While saying prayers with S.B. and Madge, Gar has a fond memory of fishing in a boat with his father as a child. He tries to ask S.B. about it, but they get interrupted by the arrival of Canon, one of S.B.'s friends.
After they go to bed, S.B. cannot sleep and ends up sitting in the kitchen. Gar wakes up and finds him sitting in the dark. As he sits down, he tries to have a nostalgic conversation with his father, but S.B. does not remember the boat he remembers. Gar flees the room, upset. When Madge comes in, S.B. tells her about a memory he has of Gar wanting to work for him in the shop instead of going to school. The play ends without Gar and S.B. making the emotional connection that Gar had so badly wanted. Private asks Public why he has to leave Ireland, and Public does not know.
