Brian Friel's Philadelphia, Here I Come! is a play about a young man named Gareth "Gar" O'Donnell, who is about to leave behind everything he knows in Ireland to move to America to live with his aunt and uncle. The story is told in a series of both flashbacks to his past and fantasies about the bright future he hopes to have in America. The play begins the night before he is due to leave, and it is here that we first see that Gar is divided on this issue in more ways than one. The character of Gar is played by two different actors, one of whom plays Gar Public, the Gar that the world sees as nice, kind, and polite, while the other plays Gar Private, who is composed of Gar's innermost thoughts, feelings, and snarky comments.

As the play progresses, we see both Gars reminisce about the girlfriend he lost, due to his own timidness and financial instability, and we see how he feels about all the other people in his life as well. Madge, the housekeeper, is like a mother to him after his own died giving birth to him. His friends—Ned, Tom, and Joe—are almost like family . . . until the night before he leaves, when he discovers that they are nothing but immature jerks who don't seem to really care that they may never see him again.

Most important of all, though, is his father. Gar Private spends the entire play calling him names like "Screwballs" behind his back, when in reality, all he wants is for his father to ask him to stay. His father, though, is completely shut down emotionally and only shows his feelings by clearly pretending to read a newspaper when Gar tries to talk to him about his plans.

The play explores the reasons behind Gar's wanting to leave Ireland, most of which involve the fact that everyone he knows has let him down somehow, and no one will ask him to stay. His girlfriend still loves him but married another man. His friends disappoint him, and his father won't say how he feels. So at the end of the play, Gar prepares to leave as planned, and the thing he wants most in the world—to be wanted—is something he never feels that he gets.