Sunday's episode of Mad Men opens with a glimpse into the life of the ever-punchable Peter Campbell. He and his wife are hosting two other couples from their block for dinner. Campbell thinks he's slick, hitting on the two women who aren't his wife. Meanwhile, though, their husbands are in the other room making passes at Trudy. Tennis, anyone?

Startlingly enough, the Campbell family might not be the only couple in such a situation. The most compelling storyline of the sixth season is, as usual, shaping up to be Don's relationship with his mistress, his downstairs neighbor, Sylvia. When we first see Don, he's alone in the elevator of his building, heading out for work. The doors open to reveal Arnold and Sylvia Rosen lightly bickering about money in the hallway outside of their apartment. Once they're alone in the elevator, Dr. Rosen complains about Sylvia and mentions that Don's lucky because Megan works. Don says that Megan doesn't earn much.

"Not yet," Dr. Rosen replies.

As the elevator reaches the lobby, Don says that he's forgotten his cigarettes and presses the button to return to his floor, though we all know that he has no intention of returning to his own apartment.

"You've got to stop that nonsense," Arnold replies, presumably about the cigarettes.

Sylvia answers the door in her nightgown with a seductive, "I knew it'd be you." The image triggers a flashback and offers our latest peek at the wizard behind Don Draper's curtain. As it turns out, Dick Whitman spent some of his impressionable adolescence living in a brothel, where one of the, ahem, professionals, seemed to have, um, taken interest in him. The flashback ends and, back in the present, a post-coital Don hands Sylvia a wad of cash. Probably a less-than-subtle nod toward a formative experience with the woman from the brothel, the transaction seems to be one that Don's experienced before.

Later, Don returns home from work to find his wife crying and his mistress consoling(?) her. Megan had just confessed that she had been six weeks pregnant, but miscarried two days earlier. Don still doesn't know that she was ever pregnant. As Sylvia goes to leave, Don thinks he's being slick when he tells Sylvia that he'll see her the next day, referring to their planned double date with the spouses.

That dinner date, though, turns out to be for two when Megan says that she's not feeling well and Dr. Rosen gets a call at the restaurant and has to dart out. Before he leaves, Dr. Rosen comments on the Vietnam War, which has a growing presence as a plot device this season. He comments that it reminds him of Cuba because no one took Fidel Castro seriously.

"We thought he was Señor Wences, turns out he's George Washington," he says.

This sentiment is echoed in Peggy's storyline for the episode. She's still incredibly friendly with Stan Rizzo over at Sterling Cooper Draper Pryce. Rizzo reveals that Heinz Ketchup came in for an informal meeting. By the end of the episode, Teddy Chaough tells Peggy that Ketchup is taking meetings. When she hesitates because of her friendship with Rizzo, Chaough takes the opportunity to explain the ad world to her.

CHAOUGH: He's not your friend. He's the enemy.

PEGGY: Well, he doesn't know that.

CHAOUGH: What are you, a priest? This is how wars are won. Your friend's mistake was underestimating you.

Later in the episode, after Don torpedoes the Jaguar sleazeball's local radio idea, Campbell storms in and chews Draper out for his antics in the meeting. Eventually, Sterling warns Don, "As my mother used to say, 'Your options were dishonor or war. You chose dishonor, you might still get war.'"

The episode ends with another flashback. We're back in the brothel where Dick Whitman is peeping through a hole in the wall, watching his pregnant stepmother have sex. One of the working girls catches him.

"You got your own room," she says. "That's how things work around here."

What if Don is underestimating his new friend, Dr. Rosen? The elevator conversation. The sly opening in House Campbell. All of the talk of underestimation.

In the premiere, Dr. Rosen uses "guys like us" talking about Don.

"You get paid to think about things that people don't want to think about and I get paid to not think about them. People will do anything to alleviate their anxiety."

I think Dr. Rosen knows what Don and Sylvia are up to. That, or I'm obsessively over-analyzing a show that's simply about drinking in the office. One or the other.