To take down South Boston's Irish Mafia, the police send in one of their own to infiltrate the underworld, not realizing the syndicate has done likewise in Martin Scorsese's multiple Oscar-winning crime thriller. While an undercover cop curries favor with the mob kingpin, a career criminal rises through the police ranks. But both sides soon discover there's a mole among them.
Henry Hill is a small time gangster, who takes part in a robbery with Jimmy Conway and Tommy De Vito, two other gangsters who have set their sights a bit higher. His two partners kill off everyone else involved in the robbery, and slowly start to climb up through the hierarchy of the Mob. Henry, however, is badly affected by his partners success, but will he stoop low enough to bring about the downfall of Jimmy and Tommy?