In a plot out of a 30's gangster picture Scorsese might have seen as a kid, small-time hood Charlie (Keitel), a native of New York's colorful Little Italy, is trying to reconcile his life as a small time thug to his strict Catholic faith. He's also constantly forced to clean up after his impulsive, erratic childhood friend and inveterate gambler, Johnny Boy (De Niro). Bonds of friendship and loyalty are sorely tested, as Charlie finds himself in deep water alongside his old buddy.

With most exteriors shot on location in and around Little Italy, the character and flavor of the neighborhood are made pungent through Scorsese's keen eye. He extracts memorable performances from Keitel and De Niro (both of whom he'd use again). The then-wiry young De Niro manages to show the tragic, pathetic side to a pretty hateful character, so we understand Charlie's compulsion to protect him. This highly personal, complex and powerful work marked a significant breakthrough for the young director, and it's still easy to see why.