Nucky makes a resolution; Margaret considers a hospital expansion; Gillian builds a new business; Van Alden stumbles onto a confrontation.

Mixing business with pleasure in New York, Nucky bristles at the collection tactics of Gaston Means, a “special investigator” with ties to Attorney General Harry Daugherty. At St. Theresa’s, Margaret is troubled when her altruism is met with resistance by both a patient and an idealistic doctor. Gyp extends his stopover in Tabor Heights, a town halfway between Atlantic City and New York, with an eye towards establishing a strategic foothold. Chalky and his daughter Maybelle (Christina Jackson) fail to agree on her future with Samuel (Ty Michael Robinson); Eli gets a new boss and faces new realities at home; a major liquor shipment takes an unexpected detour.

After tracking down a liquor thief, Nucky and Owen spend a long night hiding out from the fedswith the precocious perp. In his boss’ absence, and with Rothstein fuming over a late delivery, Mickey overrules Eli to make a routing call that will have far-reaching consequences for Nucky and Gyp. Margaret encounters a familiar face while promoting Dr. Mason’s classes at the new women’s clinic at St. Theresa’s. In New York, Lucky haggles with Joe Masseria over heroin splits, while in Chicago, Capone’s feud with O’Banion heats up when one of his collectors gets roughed up on the South Side.

Rothstein vents to Nucky and delivers a message to Gyp. Gaston Means sees an opportunity. Billie gets a new co-start. Van Alden and Sigrid receive an unexpected visitor. Gillian worries about her business.

Nucky is detained in Washington; Margaret copes with Teddy's demons; Owen investigates a suspicious fire; Richard makes a connection with a veteran and his daughter.

Eli hopes to get back in Nucky's good graces; Gillian tries to improve her future; Gyp asks for a blessing in New York.

Gillian makes her peace with Jimmy's death; Van Alden attends a meeting with Capone and Torrio; Nucky makes an offer to Andrew Mellon; Margaret makes a stand on birth control; Nucky and Owen shop for a pony; Billie considers a future in film.

Nucky vows to eliminate his nemesis. A high-profile bootlegger is arrested. Emily's birthday party is scaled down. Gillian blames Harrow for Tommy's trouble. Gyp decides to buy a town's silence.

Nucky tries to keep Jess Smith quiet and neutralize Gyp's alliance with Joe Masseria; Margaret considers an alternate future; Van Alden's side business backfires; Gyp's shipment is short; Chalky sees an opportunity.

Gyp makes his move in Atlantic City, forcing Nucky and Eddie to seek refuge with Chalky. With the Artemis Club overrun by Rosetti thugs, Gillian contemplates a business future that includes an unwelcome partner. Luciano makes a deal he’ll come to regret. Harrow loses his house privileges.

Nucky makes a deal with Rothstein as his war with Gyp Rosetti reaches its climax. Season finale.