Nucky recalls his Atlantic City roots and plots a post-Prohibition future in 1931 Cuba. Margaret finds herself in the hot seat on Wall Street when her boss decides his own future. Lucky Luciano sets in motion a plan; one that reverberates with Nucky all the way in Cuba.

Back from Cuba, Nucky meets with "Boss of Bosses" Salvatore Maranzano, sending a message to Lansky and Luciano. In Chicago, Eli and Van Alden are tasked by Al Capone's top man to recoup money lost during a federal raid. Fresh out of law school, Willie has an interview.

Margaret faces a dilemma at the bank as a result of her association with Arnold Rothstein, while Nucky entertains a prospective business partner from Boston. Luciano and Siegel meet with Narcisse in Harlem, but encounter resistance after promising business as usual.

Nucky and Margaret find common ground in Atlantic City when they face a shared dilemma, while Lucky Luciano meets Al Capone in Chicago and encounters an old adversary. Elsewhere, Sally Wheet makes a payment in Cuba as she grows fearful of a grass-roots uprising.

Chalky returns to Atlantic City with vengeance on his mind. Nucky arranges a meeting with Maranzano to discuss the Luciano threat. Eli's reunion with June takes an unexpected turn after a dinner party. Capone looks to relocate his operation. Bad news arrives from Cuba.

In Harlem, Chalky encounters Narcisse in hopes of setting Daughter Maitland free. Federal Agents enlist Eli and Van Alden to help take down the Capone organisation. Pained by a recent loss, Nucky turns to the bottle, and the company of a pair of barflies.

Nucky, at war with Luciano, looks to hold onto his assets in Atlantic City. Willie and Eli become involved in Nucky's war. Maranzano meets his fate. Nucky reads Gillian's letter from the hospital.

Nucky looks to relocate to Manhattan from Atlantic City. Margaret impresses Nucky and a grain-company stockholder. Luciano tends to unfinished business while establishing a mob commission. William shares underworld details with his boss, the U.S. Attorney.