In the early 1970s, a skilled and respected bookmaker, Sam "Ace" Rothstein, is tapped by the mob to run the Tangiers Casino in Las Vegas. His meticulous attention to detail and ability to turn the casino into a goldmine catches the attention of the mob bosses back home. Ace navigates the intricate operations of the casino world, keeping the money flowing, the clientele satisfied, and the authorities at bay. His success is marred only by the city's seedy underbelly, which includes prostitutes, hustlers, and drug dealers, all of whom are drawn to the glitz and glamor of his casino.

Ace's volatile childhood friend, Nicky Santoro, is sent by the mob to protect their investment and ensure the other casinos in the city respect their interests. However, Nicky's brutal and impulsive methods threaten to undermine Ace's control of the casino. The situation complicates further when Ace falls for Ginger, a seasoned hustler, and they enter a tumultuous marriage. Ginger's addictions and her former boyfriend, a sleazy conman, pose additional challenges to Ace's life, jeopardizing his position, his wealth, and his carefully constructed empire. As the characters' relationships become increasingly strained, their ambitions and excesses begin to lay the groundwork for betrayal and conflict within their ranks.