Philadelphia, Here I Come! centres on Gareth (Gar) O'Donnell's move to America, specifically Philadelphia. The play takes place on the night before and morning of Gar's departure to America. Gar is portrayed by two characters, Gar Public ("the Gar that people see, talk to, talk about") and Gar Private ("the unseen man, the man within, the conscience"). Gareth lives with his father, S. B. O'Donnell ("a responsible, respectable citizen") with whom he has never connected. Gar works for his father in his shop and their relationship is no different from that of Boss and Employee. Private often makes fun of S.B. calling him "Screwballs" and parodying his nightly routine as a fashion show.
Essentially, this play is a tragicomedy. It contains many comical scenes, especially the scene with Lizzy Sweeney, Gar's aunt, in which Gar decides to go to America. Despite the fact that Gar seems to have a relationship with his father no different from that of Boss and Employee, there are indications that there is love between them. In episode 1, Madge says "It must have been near daybreak when he (SB O'Donnell) got to sleep last night. I could hear the bed creaking." Other indications that SB is secretly devastated by his son's imminent departure, include his remembrance of Gar in a sailor suit proudly declaring he need not go to school, he'll work in his father's shop – a memory of an event that may not have happened, and the scene when he pretends to read the paper, but fails to notice that it has been upside-down.
Gar's reasons for going to America (he wanted to prove to Aunt Lizzie that he was not "cold like the O'Donnells"), along with his secret love for his uncommunicative father, and their desperate final, pathetic attempts to communicate make this play quite tragic.
All of the action in this play takes place within a period of a few hours on the evening of Gar's departure, but it also includes flashbacks to Gar's relationship with local girl Kate Doogan, and the visit from his Aunt Lizzie.
I've stuck around this hole far too long. I'm telling you, it's a bloody quagmire, a backwater, a dead-end! And everybody in it goes crazy sooner or later! Everybody!
— Gar Public, Episode 2
