In 1960 New York City - the high-powered and glamorous "Golden Age" of advertising - Don Draper, the biggest ad man in the business, struggles to stay a step ahead of the rapidly changing times and the young executives nipping at his heels.

Don continues to conceal his increasingly complicated personal life, even in the face of Roger Sterling's invitation to open up. Meanwhile, Peggy pines for the absent Pete still on his honeymoon while fending off the advances of several of the men of Sterling Cooper.

Pete's professional and personal lives become more complicated as he struggles to assert power in both. While facing pressure from his wife regarding a new apartment, he further alienates Don and endangers his own position at Sterling Cooper.

A taboo office romance is revealed. At a brainstorming session, Peggy proves to be more than a secretary, opening up new opportunities for her at Sterling Cooper. Meanwhile, Rachel faces her conflicted feelings for Don after he seeks out her advice on a new campaign.

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.

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.