While Don struggles to control his problematic love life, he tries to keep the agency from losing a big tobacco account.

Betty consults with a specialist about her health issues; Don is pressured to help with Nixon's presidential campaign; Peggy fends off the advances of a copywriter.

Upon returning from his honeymoon, Pete is troubled by what happened with Peggy after his bachelor party. Don's professional relationship with Rachel undergoes significant changes.

Don teaches Pete a lesson when he oversteps his authority in dealing with a valuable client. At home, Pete is pressured from his newlywed bride to buy their own apartment unit.

Don's past catches up to him when he wins an award and gets his picture on a prominent industry periodical. Ken makes his colleagues jealous when he gets a short story published in a national monthly magazine.

Rumors spread in the office about a surprise romantic affair. Peggy's ideas get noticed during a pitch meeting and her future at the agency begins to look more promising. Don asks Rachel's advice about an ad campaign.

Roger joins Don for an evening of dinner and drinking, during which Roger's behavior leads to a rift in their friendship. Though Don accepts his apology, there are further consequences for Roger. Pete faces trouble at home as he continues to struggle with the demands of his new marriage.

Don is tormented as pieces of his secretive past begin to haunt him. Peggy’s new success at work, and resulting boost in confidence, threaten her office relationship. Salvatore (Bryan Batt) gets a little too close with a client.

A rival ad agency courts Don, involving Betty in their attempt to lure him from Sterling Cooper. As the presidential campaign heats up, the agency looks for new ways to counter the latest Kennedy ads. Tempers flare over Peggy.

Don loses an account. Roger, stuck in the city for Labor Day weekend, attempts to cheer him up. Meanwhile, Joan has a night out on the town with her roommate.

Peggy is given a difficult assignment. Roger's work problems provide new opportunities for Don, and Pete grows more frustrated. Betty finds a new outlet for her growing dissatisfaction.

On election night, the Sterling Cooper staff pulls a rowdy all-nighter while watching the returns. Pete's ambitions cause him to directly challenge Don.

As Thanksgiving approaches, Don's work responsibilities interfere with his domestic life. Peggy is given a new opportunity, provoking the ire of some of her colleagues. Betty makes a startling discovery.