Chronicles the life and times of Enoch 'Nucky' Thompson, Atlantic City's undisputed czar at a time when Prohibition proved to be a major catalyst in the rise of organized crime in America. Season three begins on New Year's Eve 1922-23. The roaring '20s are about to start; though the economy is booming, alcohol has become scarce, competition is fierce, and gangster violence is heating up.

Atlantic City, February 1924: Picking up 8 months after the events of Season 3, Nucky Thompson is laying low at the end of the Boardwalk after barely surviving an overthrow by gangster Gyp Rosetti. But the calm will be short-lived, as Nucky faces new challenges, including a clash with a violent Harlem power broker, a battle with his brother Eli over Eli's college-age son, and the irresistible lure of lucrative- and perilous- opportunities in Florida....

Atlantic City, 1921. In a city whose fortunes have soared in the wake of Prohibition, Nucky Thompson is paying a steep price for wielding ultimate power in 'the world's playground'. Though the 1920 election is over, Nucky finds himself the target of a federal investigation for vote tampering, and an insurrection by those he counted among his closest allies.

Beginning six years after season four, the country is in the throes of the Great Depression--a stark contrast with the Roaring Twenties. With the end of Prohibition in sight, Nucky is looking to legitimize himself by forging alliances with liquor producers, including Bacardi in Cuba.

A period drama set in Atlantic City, following the life and times of Nucky Thompson, the undisputed political and criminal mastermind whose grip on power and control of the city's liquor supply is under constant threat.