This week's new episode of 'Boardwalk Empire' continues to set the table for dark things to come. In "William Wilson," taken from the Edgar Allan Poe short story of the same name (and hardly subtle), we learn a little about identities and shadows -- and at long last, we learn a little truth about our pal Agent Knox. 

Agent Knox is really Agent Tolliver, and there's a reason why Nucky can't seem to get much more than a conveniently straight story out of Gaston Means. Knox/Tolliver has Means in his pocket, and he's the only person standing between Means and prison bars. Along with a real identity, we get a little complexity from Knox -- Hoover, who has just become head of the bureau of investigation, takes all the credit for Knox's hard work trying to tear the lid off of the nation's bootlegging criminal ring, sending Knox straight for a bottle of whiskey.

In Edgar Allan Poe's 'William Wilson,' the lead character of the same name encounters a doppelganger of sorts at school. The fellow has his same name, mannerisms, and even sort of looks similar, and his persistence in shadowing the narrator drives him to murder the double -- and thus, he essentially murders himself.

Knox's shadow, it seems, is Hoover, with whom he attended college. While both are over-achiever types, Hoover has always been more socially and politically appealing, allowing him to succeed just a little more, the shadow always a step ahead of the body.

'William Wilson' is also the story Willy Thompson is reading in class, and its themes are enough to finally send him over the edge. Henry wasn't much different from Willy, in all truth, and so Willy's murder -- however inadvertent -- of his classmate is chipping away at his humanity. We see it in his sullen eyes while his girlfriend paws at him, and we see it on his face when his parents admonish him for even thinking of leaving school. But the truth is he checked out weeks ago, even before he officially withdrew. Willy is drawn to his uncle Nucky's life, even more so now that he's a murderer -- what life could he have left to live, constantly carrying this burden, this shadow of Henry's life, behind him? Perhaps getting into business with his uncle is the life he thinks he deserves.

While chatting with Gaston Means, Nucky gazes off and wonders, "You ever wake up, have a vague feeling of unease? Like you know something's wrong but you can't put your finger on it yet." It's not as if he's really looking for a response from Gaston, but it's an idea that permeates the episode. Something isn't right -- a lot of somethings aren't right, but there's a lot to be seen if everyone could just remove their blinders. Nucky is blinded by his ambition; the deal in Tampa will surely only bring more trouble, and he's too trusting to see that Gaston Means isn't telling him everything he needs to know about Agent Knox and the storm that's brewing -- ever so slowly -- at the bureau of investigation. Means tells Knox that past behavior is the best indicator of future behavior. Means has always given Nucky the information he needs, so why distrust him now? You can hear him try to convince himself as he convinces Eli that Knox's handkerchief meant nothing.

And if past behavior is truly the best indicator of future behavior, then Nucky has a hard road ahead.

The women this week perhaps carry the most interesting ideas of shadows and doubles -- Margaret, who assists her boss in making business transactions with a little con about her "husband" purchasing shares in the company, runs into her own shadow in the form of Arnold Rothstein, going under the alias Abe Redstone. It's a (darkly) humorous scene that brings some nervous levity to the episode, as "Abe" gives Margaret (now under the name Mrs. Rowan) $100 and asks that they enter a mutually beneficial agreement to be discreet about their true identities. (Side note: I know it's horribly wrong, but their interactions this week make me long for Margaret and Rothstein to get their own romantic subplot. Their chemistry is electric.)

Daughter Maitland has a shadow of her own, too -- 'Boardwalk Empire' did excellent work this week and last week making us buy into the idea that Daughter truly has feelings for Chalky. And maybe she still does somewhere in there, but she is, as assumed, merely a carrot meant to lead Chalky wherever Narcisse desires him to go. And right now, that means an agreement to let Daughter stay at Onyx in exchange for allowing Narcisse to open one of his parlors of enlightenment. As Daughter tells the story of how her prostitute mother was murdered by a violent john after she attacked him with a jar of lye, and how Dr. Narcisse rescued her and blessed her with a path in life, we know -- but Chalky does not, blinded by lust as he is -- that there's something darker to this tale, as there undoubtedly is when Narcisse is involved. Sure enough, Narcisse reveals the scars from that jar of lye, also revealing an unsettling father/Daughter (clever) dynamic.

Duality is all over this episode, from Narcisse simultaneously peddling and trying to rescue the black community from the effect of heroin, to the bedroom of Gillian Darmody. You'd think she would dispense with the dainty, damsel in distress facade already, especially with Roy Phillips nursing her out of heroin withdrawal. Gillian, broken down and sweating, writhing and vomiting, still struggles to maintain some sense of control over how she's perceived by others. Roy, on the other hand, admits that he filed divorce papers the day after he met Gillian. I still continue to believe that Roy cannot possibly be this kind -- either he's a new thing for Gillian to destroy, or he'll destroy her. There's no way this story goes happily ever after. I don't buy it.

Sort of separate from the rest of the episode is the business in Chicago, where Al tries to convince Johnny Torrio that Dean O'Banion sicced the cops on Frank. But Torrio doesn't buy it until later -- just as he signs the papers to purchase a brewery from O'Banion, the cops bust in. Torrio's in jail for several days, and pays a hefty bond to get out, while O'Banion's charges are dropped and he's out immediately. The result? Torrio grants the bloodthirsty Al his wish and commands him to kill O'Banion. This could get pretty brutal in the next couple of weeks.

Elsewhere in the episode: Dunn Purnsley knifes a priest, and Luciano gets sent back down to Tampa to broker a heroin deal!