Boardwalk Empire Season Finale recap Macall B. Polay/HBO Stephen Graham (center) on 'Boardwalk Empire' We begin this week with a crucial spoiler alert: Watch season finale "Margate Sands" before reading another word. Atlantic City is in chaos, and the war has become a dirty street fight. Men trying to surrender are shot dead; shotguns are deployed against those who haven't so much as a pen-knife. One guy is killed while he reads a newspaper, and we see at least one actual back-stabblng. This season of Boardwalk was about Nucky's evolution from splendid huckster to cold gangster. That evolution began with last season's finale, when Nucky made the choice to shoot his protege Jimmy in the face. At the end of this season's finale, Nucky reclaims his empire but tosses his signature carnation onto the boardwalk. He was never a soft man, but he will from now be a hard man. His victory is won at great cost - so many guys die that Atlantic City in the 1920s seems more dangerous than Gallipoli. In Chicago, Torrio asks Rosetti a good question about all the killing: "For what?" Twelve of Torrio's men have died - but why? Rosetti gives an answer you might hear during a game of Monopoly: Rosetti has control of Nucky's warehouse and his hotel. MORE: Boardwalk Empire Watch: The War Begins One of the most skillfully wrought story lines of this season was the reconciliation of the Thompson brothers. Beginning in "Sunday Best," the extraordinary episode in October, Nucky began to make an uneasy peace with Eli. By the finale, he knows he needs his brother, and he also seems to have an affection for him that we've never seen. One moment of tenderness comes at what may be Nucky's lowest point. When Rothstein calls to offer a deal to end the war, Nucky holds the receiver so that Eli can hear: Rothstein will require 99% of Overholt distillery's profit in exchange for arranging Masseria's retreat from the war. Meantime, Margaret is in Brooklyn to get Owen's baby aborted. "I'm completely lost," she says - something the rest of us have known since the beginning of the season. It will be interesting to see how the writers work around her departure from Nucky - and what I imagine will be her eventual return to him. MORE: Boardwalk Empire Watch: The Crate I'm going to skip over the history lesson involving Meyer Lansky, Lucky Luciano, Arnold Rothstein and the rest. It's artfully written - and beautifully shot, as usual - but the New York City mobster story line always seems a bit forced. What didn't seem forced was the elegant scene at Artemis in which Harrow effortlessly executes what's left of Rosetti's army. The music fades; the building creaks; Harrow kills people. The scene shot rotating over Harrow's head was both horrifying and exhilarating. I watched it at least three times. Finally, good riddance to Rosetti - one of the most overwritten and least interesting characters ever to appear on HBO. See you next season. MORE: Boardwalk Empire Watch: My Ears Are Ringing