"When Billy Summers was twelve years old, he shot and killed his mother's boyfriend after he kicked Billy's sister to death. At 17, he enlisted in the army. At 18, he was a sniper in Iraq and involved in the deadly battle to recapture Fallujah. For nearly twenty years, he's worked as a paid assassin. He's a good guy in a bad job, and he wants out. He takes on a very complicated, very lucrative job that he hopes will be his last. He's got a perfect...

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....