Las Vegas, 1973. Gambler and bookmaker, Sam "Ace" Rothstein, becomes boss of one of the largest casinos in the city on mafia orders.
The Chicago Jew, Sam Rothstein (Robert De Niro), nicknamed the Ace by everyone, is a professional gamer and genius gambler. The Mafia draws him to Las Vegas, entrusting him with an important mission. Thanks to influential protectors, Sam takes control of several profitable casinos. He is helped by his best friend, Nicky Santoro (Joe Pesci), a psychopathic killer who takes care of taking down uncomfortable clients.