Whether by accident or design (I'm voting design), Boardwalk Empire presents a bona fide King Arthur story in the telling of the tales of Prohibition-era Atlantic City, Nucky Thompson, and Jimmy Darmody. All the characters are here: Gillian as the mother-temptress Morgause; Margaret and Lucy as twin Guenevers and Owen as Lancelot; and Jimmy and Nucky in the roles of Mordred and Arthur. The painted whore that is Roaring Twenties Atlantic City is the dark mirror image of Camelot: a false golden era replete with crime and controlled by robber barons, bootleggers, and mob bosses. Above it all Nucky looms, his fingers in every pie in existence, struggling to keep his motley array of Companions (Neary, Doyle, O'Neill, Eli) in line, and treating with rival kings (Torrio, Rothstein, the D'Alessios, Chalky White). A bootlegging, philandering, glad-handing criminal and hypocrite, Nucky embodies the trope that Might makes Right--the very opposite of what Arthur traditionally stands for.
Jimmy returns from the Great War, considering himself proven as a man on the field of battle and itching for more power and responsibility in Nucky's operation. His bastard's birthright is double, having been born of the Commodore, whose power is fading (and who represents Lot, a petty king who is ineffective and then dead in the Arthur myth), and raised by Nucky, still in his prime. He expects to inherit, and soon...and a stew of resentment begins to seethe as he sows the seeds of his own destruction. In an attempt to strike out on his own he betrays Nucky, gathering around himself other betrayers, including his father, the Commodore, Gillian, and Nucky's brother Eli. Jimmy's wife Angela can be viewed as either Gareth--the innocent mowed down by accident, a victim of the strife between Mordred and Arthur--or Elaine, a woman slain by her attempts to control her own life. His mother Gillian is the quintessential Morgause; simultaneously she is a mother figure, raising Jimmy and then his son, and a sex bomb who takes partners as she will, including men much younger than herself. The pivotal moment of incest, which in the Arthur stories occurs either between Morgan le Fay and Arthur or Morgause and Arthur, occurs in Boardwalk Empire between Jimmy and Gillian, read as Mordred and Morgause.
Into the midst of Nucky's neat operation trots Agent Nelson van Alden, the most uptight lawman in New Jersey and a man possessed by the need to take Nucky down. In the Arthur stories, the character of Maleagant (or Maleagrance) is a villain, a rival petty king who kidnaps Guenever; since Boardwalk Empire's protagonists are villains themselves, it makes sense that the ostensible "good" character of van Alden would oppose Nucky and what he stands for. His relationships with the dual Guenever characters of Margaret and Lucy cement his characterization, as he threatens the security of Nucky's throne by lusting after Margaret and encouraging her to betray Nucky, and impregnating Lucy. Margaret, in her turn, cheats on Nucky with his driver/bodyguard Owen Sleater, an act which heralds her (re)turn to religion and belief that she is being punished for her sins. The Guenever of the Arthur stories is notably barren, of course, but the functions of the traditional Gwen and the two characters we read as her avatars in Boardwalk Empire are similar: to be beautiful, ornamental, and available for sex, to complement her man in social situations, and to not comment on or be involved in business matters.
The series-wide theme of the current generation's effect on the rising generation occurs repeatedly in various guises--Jimmy's son Tommy ultimately loses both parents and will presumably have his future shaped and warped, as Jimmy's was, by Gillian; Nucky's lack of children is a thorn in his side and perhaps the reason why he takes such pains to hold onto Margaret and her children by her previous husband, and we see his effect on Margaret's son already (in Nucky's episode of arson on his childhood home); Eli's huge brood of children is arguably his only success in life, that of reproductive, evolutionary prowess; van Alden's daughter, though born out of wedlock, is precious to him and it seems that he will have the raising of her after his wife divorces him (since Lucy has no care for her daughter). So, in a phrase from The Mists of Avalon, what of the king stag when the young stag is grown? Jimmy is ready to take over for Nucky but Nucky isn't ready to relinquish the reins. Humanity spends its life fighting the natural course of things, the cycle of living and dying. No man will admit when he should retire--encapsulated perfectly in the Commodore's fight to hang onto life and his relevance to Atlantic City's community. Nucky too is incapable of giving up his power, and Jimmy's attempt to take that power for himself results in his downfall.
Season 2 of Boardwalk Empire ends with Mordred dead and Arthur still in control; but where will it go from there? The saga of Arthur and Mordred culminates in both men's deaths (or with Arthur retiring to Avalon). Obviously the show diverges by necessity at this point, and I look forward to seeing what the writers throw at us next...though clearly I will miss parsing its plots and characters in terms of my favorite mythology.