Don Draper's identity continues to mutate as “Mad Men's" sixth season enters its final stretch. “The Better Half” is one of the series' most self-referential episodes yet, full of delicious nods to the show's preoccupation with dualism and a fourth-wall-breaking inside joke about the multiple actors who have played Bobby Draper.

The transparency of “The Better Half” has a behind-the-scenes feel to it – a sense that the actors are aware of the audience, rewarding us for our investment in their characters. Questions are answered and long-simmering tensions are broken. “The Better Half” is as straightforward and predictable as “The Crash” was surreal and opaque, and proceeds as though the office-wide drug binge never happened. (Maybe it was all in their -- our -- minds?)

The first few seasons of “Mad Men” established Joan Holloway and Peggy Olson as yin & yang archetypes of female identity: Joan the buxom, subservient sex symbol and Peggy the buttoned-up careerist. Megan Draper has mostly walked the line: Eschewing a traditional female role in favor of advancing her own career, but more than happy to use her sexuality to get what she wants – whether it's a rich husband or an expanded role on a soap opera. Betty Draper/Francis has always been more of a Joan than a Peggy, though since she gained weight and went brunette she's been a little harder to pin down. But now that she's lost the extra pounds and the brown hair dye, Betty is back in her element, enjoying renewed attention from men everywhere, including her ex-husband. In “The Better Half,” Joan and Betty have the upper hand while Peggy and Megan drift lonely and rudderless as their power slips from their fingers. Megan's crisis of confidence could very well be temporary, but Peggy's whole world has come crashing down, and there's no one there to help her pick up the pieces.

Matthew Weiner and Erin Levy, who wrote the episode, did us a favor by showing Abe at his ugliest just before he broke up with Peggy. That relationship was bound to end sooner or later, but nothing hurries a breakup along like a knife wound to the gut. Abe had already been stabbed once earlier in the episode (this time on purpose), upon emerging from the subway in their Upper West Side neighborhood. To Peggy's chagrin, Abe refuses to provide a description of his assailant to the police. After someone tosses a rock through their bedroom window, Abe agrees to putting the building on the market, admitting that maybe he and Peggy aren't “cut out to be pioneers.” Peggy responds with inappropriate, infuriating gratitude: “You'd do that for me?” The only thing that Abe has “done” is dictate the terms of the living arrangements that Peggy has funded completely on her own. We've known for awhile the Abe was an entitled layabout, but his parting words to Peggy as he lay bleeding in the ambulance suggest there might be something even more sinister going on. After telling her that she will “always be the enemy,” he says that her stabbing him will make for a great ending to the story he's been working on. What's this story about, exactly?

The biggest story of this week's episode, of course, is Don and Betty's tryst at Bobby's summer camp. Like Abe and Peggy's split, a reunion was only a matter of time, but I didn't expect it to happen quite so soon. Still, it was obvious when Betty and Don ran into each other at a gas station that something had shifted between them, and things only get cozier after a parent-child singalong to “Father Abraham.” (This is also where things get meta: Bobby, who has been portrayed by four different actors so far, explains that he is “Bobby Number 5” at camp. Bobby Number 1 has gone home.) Betty eagerly and confidently lures Don into her motel room, but she doesn't want anything beyond a one-night stand. Their frank pillow talk betrays a baseline trust and familiarity we don't often see; still, Betty is content to leave the indiscretion behind them. In her mind, she's won, and she's not about to look a gift horse in the mouth.

Fresh from the minor, but still significant, victory of sparing Bob Benson during the post-merger layoffs, Joan rejects Roger Sterling's puny efforts to act as a father figure to Kevin. Roger hasn't acknowledged his and Joan's son all season long, but after his daughter scolds him for taking her four-year-old son to see “Planet of the Apes,” Roger shows up at Joan's apartment, unannounced, with a gift of Lincoln Logs. He's flummoxed when Bob Benson answers the door, and claims not to immediately recognize him. It's unclear if Roger really didn't know who he was, and the nature of Joan and Bob's beach outing is also a bit vague. Are they just friends? Bob, solicitous as ever, offers to leave the two of them alone, but Joan rushes Roger out the door. Back at the office, she tells him she'd rather Kevin believe his father is a brave war hero than a man who can't be counted on from one day to the next. Either way, the father will be absent; why not let Kevin have the one with a better story?

For a hot minute, Peggy probably saw a silver lining in the abrupt end to her relationship: Now she would be free to carry on with Ted Chaough, who had earlier confessed to being in love with her. The morning after the breakup/stabbing, a disheveled Peggy marches into Ted's office to deliver the news. But Ted has already moved on (or at least pretended to), and tells Peggy to get back to work after offering her a weak platitude. The episode closes on Peggy standing in the hallway as Ted and Don each close their doors on either side of her. Peggy is alone again, and this time, nothing is on her terms.

Miscellaneous observations:

In an early scene, Megan complains to Don about her struggle to play twins on "To Have and to Hold": Her director doesn't think she's playing them differently enough. “They are two halves of the same person and they both want the same thing,” Megan says the director explained, “And they are trying to get it in different ways.” This is clearly a reference to Don's split identity, though what exactly do Don Draper and Dick Whitman both want?

We noticed two edits that seemed aimed to create some kind of continuity (and there may have been more we missed.) Just after Roger closes the door to Joan's office, Bob Benson opens a seemingly identical door, before telling a yet-unknown person that “something delicate” has come to his attention. For a second, until we see that he is in Pete's office, it seems as though he could be talking to Joan. (But other than that maybe-allusion, this is the first episode of season six that has not included a reference to the Joan-Jaguar prostitution scandal.) Also: Peggy and Abe's ambulance breakup scene cuts to Megan alone in her apartment, and we hear the sound of a siren that seems like it could be coming from the same ambulance. But Megan and Don live on the Upper East Side, and Peggy and Abe were coming from the Upper West. So it would seem unlikely, unless Lenox Hill Hospital in the East 80s was the closest to Abe and Peggy's place. We don't know how far north they live on the Upper West Side – but if they live in or near the 80s, cutting across Central Park to Lenox Hill probably would have been the fastest route to medical care.

Ken Cosgrove was completely absent from this episode. Maybe all the tap dancing tired him out. Hope to see him again next week.