In the summer of 1979, 19-year-old Irish-American gas jockey Shane O'Shea lives in Jersey City, New Jersey with his widowed, conservative father Harlan and two younger sisters Grace and Kelly, both named after Grace Kelly. Shane longs for a more glamorous life across the river in New York, so one night he talks his two friends into going to Studio 54; however, gay club owner Steve Rubell only picks Shane to come inside. Once inside, Shane is exposed to the flashy, hedonistic world of 54, with unbridled alcohol, drugs, and open sex. Against his father’s wishes, Shane returns to 54 the next night and is hired by Steve as a busboy, befriending fellow busboy Greg Randazzo and his wife Anita, a coat-check girl and aspiring singer. Shane eventually moves out of his family's house in Jersey City after fighting with his father over his new job, and moves in with Greg and Anita in New York, who both become a new surrogate family to him.