Set in the late 1970s, the story unfolds through the eyes of Shane O'Shea, a 19-year-old gas jockey from Jersey City, New Jersey. Living with his widowed, conservative father Harlan and his two younger sisters, Grace and Kelly—both named in honor of the late Princess Grace—Shane feels trapped in his mundane life after the loss of his mother when he was just 12. The allure of a more exhilarating life in New York City captures his imagination, pushing him to make a dramatic transformation in appearance and convincing his friends to venture to the legendary Studio 54.
Upon arriving, Shane is thrillingly chosen by club owner Steve Rubell to enter the nightclub—after a cheeky shirt removal, of course—while his friends are left outside. Stepping into Studio 54, Shane is instantly immersed in a world pulsating with glamour, hedonism, and excesses of all kinds. The thrill of this vibrant nightlife hooks him, prompting him to plan future visits despite his father's disapproval.
The very next night, Shane boldly borrows his father's car and returns to the club, where he is promptly hired as a busboy. Here, he strikes up a friendship with fellow busboy Greg Randazzo and his ambitious wife, Anita, both of whom share similar dreams of escaping their current lives. While Shane embraces this new chapter, he stumbles into a romantic encounter with Patti, a regular at the club, on his very first night as a busboy, sending his life into a spiral of exciting escapades.
Ambition drives Shane as he aspires to climb the ranks within the club. His fortunes change swiftly when Billie Auster, a sophisticated regular at 54, takes an interest in him during a drug-fueled rendezvous, which leaves Shane further enmeshed in the decadent lifestyle of New York's elite. As he grabs the spotlight and is nicknamed "Shane 54," he becomes engulfed in the highs and lows of fame, facing drug use, fleeting romances, and a battle for identity amid the superficiality surrounding him.
However, Shane’s ascent comes with personal sacrifices—his relationships with Greg, and his family begin to fray. Accusations of conceit arise when they suspect him of pursuing Anita, while his father's rejection stings, particularly after he hears rumors of Shane's drug use at the club. Amidst the chaos, Shane finds a brief flicker of happiness in a romance with his ideal woman, Julie Black, an aspiring actress from Jersey.
Yet, as the calendar flips to a new year, the dazzling life Shane thought he desired begins to crumble. After catching Julie with Roland Sachs, a casting agent, Shane feels betrayed and sickened, unable to reconcile his own actions. The tragic death of Mona, a regular who succumbs to a drug overdose during Anita’s big performance, rocks Shane to his core. Refusing to carry on business as usual, Shane clashes with Steve and is eventually fired, culminating in his dramatic ejection from the club, echoing the shameful arrival he once experienced but now leaves shirtless and humiliated.
The film concludes with a glimpse into Shane's future, revealing that while Studio 54 faced its demise in 1986, he found solace in changing his life path. His relationship with Julie persists and flourishes, even as he pursues higher education and manages a restaurant at night. Though his friendships with Greg and Anita drift, they achieve their own modicum of success within their respective industries. In a bittersweet reunion at the club's comeback night, Shane realizes that while the party may have ended, the memories and connections forged are everlasting, encapsulating the fleeting nature of youth and ambition. As Shane poignantly reflects, "the party was over."
