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.

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.

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.

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.

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.