Esther Randolph's case is weakened by the sudden death of one witness and the sudden marriage of another. Jimmy turns away from the influence of others, including his mother. Nucky, acting the family man to Margaret, faces a difficult, bottom-line business decision.

Eli braces for the worst as Agent Knox launches his plan to bring Nucky down. Capone and Torrio reach an agreement in Cicero. Chalky looks to settle scores. Richard steps forward to save Tommy, at Gillian’s expense

Despite being publicly embarrassed by legal trouble, Nucky's biggest concern may be holding on to his private army in a battle for control of Atlantic City. Meanwhile, Jimmy pitches a business deal to Arnold Rothstein in New York, but may have more in common with Meyer Lansky and Lucky Luciano. Margaret draws on past experience to retrieve some valuable information, Chalky clashes with a fellow inmate, and an Irish nationalist comes to town looking for support.

With Margaret pondering the consequences of sin, Nucky prepares her for a worst-case scenario as Esther Randolph plays out her trump cards. Jimmy revisits his college days with Angela and Gillian. Mickey Doyle chafes at sharing his liquor profits. Eli refuses to cop a plea. Nelson's past comes back to haunt him, tipping the scale in Nucky's favor.

Nucky heads to Philadelphia; Agent Knox detains Eddie Kessler to obtain information about Nucky's organization; Gillian tries to score a fix; Van Alden is recruited by the Capones.

Nucky plans to relocate to Manhattan; Margaret impresses Nucky and a grain company stockholder.

Nucky reminisces about catching the Commodore's eye; Nucky joins Sally Wheet in Cuba; Margaret finds herself in the hot seat; Chalky tries to extricate himself from a difficult situation; Lucky Luciano sets a bold plan in motion.

January 1920. On the eve of Prohibition, Atlantic City's Treasurer, Nucky Thompson, condemns alcohol at a Women's Temperance League meeting, where he is noticed by Margaret Schroeder, a pretty, pregnant housewife who comes to him for help in getting her abusive husband Hans a job. Later that evening, the duplicitous Nucky privately tells his ward bosses about the opportunity to make huge profits selling bootleg liquor. At a countdown-to-midnight blast at Babette's Supper Club, he assures Jimmy Darmody, a recently returned WWI vet, that his appointment as "Man Friday" to the new Chief Clerk of the Fourth Ward, Paddy Ryan, will lead to bigger things. Jimmy, meanwhile, has higher aspirations and ends up making an alliance that could have dire consequences for both him and Nucky.

"Paris Green" is the 11th episode of the first season of the HBO television series Boardwalk Empire, which premiered November 28, 2010. The episode was written by supervising producer Howard Korder and directed by Allen Coulter.

Nucky has reservations about investing in a Tampa land deal engineered by transplanted bootlegger Bill McCoy. While there, he meets speakeasy owner Sally Wheet. Valentin Narcisse books a sexy jazz singer, Daughter Maitland, to perform at the Onyx, and gauges Dunn Purnsley’s allegiance to Chalky. Willie, Eli’s son, turns to Mickey Doyle and his bootleg warehouse to elevate his social standing at college. Gillian agrees to pose as Roy Phillips’ wife to impress a possible partner. Harrow tries to bury his past, though not before taking care of some unfinished business with Emma.

Nucky asks for Margaret's assistance in backing his mayoral candidate with the passage of women's right to vote, leaving her conflicted about her role. Doyle switches sides back from Rothstein, which leads Nucky to conspire with Chalky against Lansky and the D'Alessios. Angela witnesses Jimmy's violent side against her photographer friend, and considers leaving Atlantic City for good in the aftermath. Van Alden grapples with his emotions, and has encounters with both Margaret and Lucy.

In the wake of a personal loss, Nucky solicits advice on his political situation from Arnold Rothstein, while Eli remains suspicious of his brother’s actions. Nucky finds himself in the unfamiliar position of showing gratitude toward a federal agent. Angela meets a new friend at the beach, and eavesdrops on her husband’s treachery. Nelson gets a nanny. Nucky approaches Owen with an overseas proposition. Jimmy flexes his muscles, at Mickey Doyle’s expense.

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.

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.

Now working as a “delivery man” for Dean O’Banion, Van Alden is ordered to keep tabs on Al Capone, joining the ascendant mobster to help keep Cicero voters “informed” at a political rally. Dr. Valentin Narcisse arrives in Atlantic City, clashing with Chalky and Nucky over the loss of an employee. In Washington, Agent Knox aligns himself with J. Edgar Hoover, acting director of the Bureau of Investigation. Harrow fails to finish a job in Milwaukee, while Eddie demands a promotion after 11 years of service. With a business opportunity on the horizon, Nucky departs for Florida.

After his father Ethan is injured in a fall, Nucky uses the opportunity to refurbish his childhood home. On a double-date with new friend Annabelle and her beaux, Margaret tries to get Nucky to open up about some painful childhood memories. During a visit to an army hospital, Jimmy befriends disfigured vet Richard Harrow, whose sharp eye proves invaluable. Van Alden gets a lead on the woods massacre.

Arriving in Belfast, Nucky and Owen meet with IRA leaders with a barter proposition. Meanwhile, in Atlantic City, Jimmy and his partners broker a deal with George Remus for his “medicinal” alcohol before taking a break to see/hear the Dempsey fight. Margaret frets when Emily’s illness takes a turn for the worse. Dunn Purnsley orchestrates a worker’s strike at the Ritz. Waxey Gordon takes action against Manny Horvitz in Philadelphia, and Randolph and Clifford Lathrop grill Halloran about Nucky’s past.

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

Nucky enlists Eli and Agent Knox to check the cargo in the Florida shipments; Margaret considers making a deal with Rothstein; Capone grows suspicious of Torrio; Nucky faces a dilemma.

Nucky deals with the fallout from Jimmy's rogue heist, sending Eli to sow the seeds of doubt in the mind of Margaret, who seeks help in the wake of her husband's demise.

An unlikely witness to the woods massacre threatens to expose the perpetrators, sending both Eli and Van Alden rushing to the hospital. Margaret starts a new job at an upscale French dress shop at the Ritz, while Chalky's team pays a heavy price for taking over Mickey Doyle's bootleg operation.

Nucky faces Election Day in Atlantic City and pulls out all the stops to keep power in Republican hands. Torrio brokers a discussion between Nucky and Rothstein to resolve their growing gang war, as well as Rothstein's looming federal indictment over the World Series. Both Jimmy and Eli voice their growing resentment towards Nucky, and find they have an ally in the Commodore. Van Alden seeks a sign on whether or not to leave Atlantic City, but receives unexpected news from Lucy. Margaret weighs new information about Nucky's first marriage and her uncertain future to make a final decision on her role in his life.

After a dispute with his enemies, Nucky brings in a surprise guest speaker at a Memorial Day dedication for war veterans. Running out of options, Eli questions his allegiances, but it ends up sending him deeper into the hole. Nucky hires a new lawyer. Jimmy is taught a lesson by one of the Commodore's men that he won't soon forget. Richard decides to go hunting in the forest.

Undercut by Nucky, who has a new source for alcohol, Jimmy and his partners look to cultivate a new revenue stream in Atlantic City. With the peak tourist season approaching, the Commodore’s crew faces a choice in dealing with the city’s striking workers; either negotiate or fight back. Fearing that sin has led to misfortune, Margaret approaches Father Brennan with an “act of devotion.” Nucky gets a new lawyer. Van Alden faces an uncertain future. Manny Horvitz takes exception to a debt payment.

Following his battle with Gyp Rosetti, Nucky makes a peace offering to Joe Masseria while working the odds with Arnold Rothstein. While Chalky is busy running the Onyx Club on the Boardwalk, the impulsive Dunn Purnsley clashes with a booking agent. Fresh-faced Federal Agent Warren Knox arrives in Atlantic City to learn the ropes from Agent Sawicki. Gillian seeks custody of her grandson, Tommy, while trying to find a “good” man to keep the Artemis Club afloat. Eli’s college-age son, Willie, turns to Nucky for career advice. Al Capone enlists his brothers, Frank and Ralph, to help him expand his business in the Chicago suburb of Cicero. Richard Harrow returns to his violent ways.