It's five years later and Tony Manero's Saturday Night Fever is still burning. Now he's strutting toward his biggest challenger yet - making it as a dancer on the Broadway stage.

Richard Fleischer repeatedly turned down Dino De Laurentiis' overtures to direct the film. He ultimately relented when he realized that the best way to make the film was to shoot it straight and tell the story as truthfully as he could.

Bill, a wealthy businessman, confronts his junkie daughter's drug-dealing boyfriend; in the ensuing argument, Bill kills him. Panic-stricken, he wanders the streets and eventually stops at a bar. There he runs into a drunken factory worker named Joe, who hates hippies, blacks, and anyone who is "different", and would like to kill one himself. The two start talking, and Bill reveals his secret to Joe. Complications ensue.

Mark Kaminsky is kicked out of the FBI for his rough treatment of a suspect. He winds up as the sheriff of a small town in North Carolina. FBI Chief Harry Shannon, whose son has been killed by a mobster named Patrovina, enlists Kaminsky in a personal vendetta with a promise of reinstatement into the FBI if Patrovina is taken down. To accomplish this, he must go undercover and join Patrovina's gang.

Frank Serpico is an idealistic New York City cop who refuses to take bribes, unlike the rest of the force. Frank's actions get him shunned by the other officers, and often placed in dangerous situations by his partners. When his superiors ignore his accusations of corruption, Frank decides to go public with the allegations. Although this causes the Knapp Commission to investigate his claims, Frank has also placed a target on himself.

Tony spends his Saturdays at a disco where his stylish moves raise his popularity among the patrons. But his life outside the disco is not easy and things change when he gets attracted to Stephanie.