The risqué private life of Chicago mob gangster and spy, Sam Giancana gets unwanted attention from the FBI and the press just as the CIA prepares its top-secret invasion of Cuba at the Bay of Pigs.

Facing political humiliation, the Kennedys double down on their plot against Castro. Meanwhile, things get personal for gangster spy Johnny Roselli and he decides to take matters into his own hands.

Conflict between the US and Castro boils over when the CIA's actions in Cuba lead to a nuclear showdown with the Soviets. Roselli must contend with news of a national tragedy in Dallas.