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 one of the copywriters.
Upon returning from his honeymoon, Pete is troubled by what happened with Peggy at 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's new bride pressures him 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.
Betty is used by a rival ad agency to woo Don away from Sterling Cooper. Peggy is sought after by two romantic rivals. The agency tries to spruce up their Nixon presidential campaign, endeavoring to counteract a successful Kennedy ad.
Don loses an important account and Roger, who happens to be stuck in the city on Labor Day, attempts to cheer him up. Meanwhile, Joan and her roommate go out to paint the town.
While Peggy gets assigned to a difficult project, Don grabs ahold of an opportunity provided by Roger's latest work problems. Pete has more problems at home and at the office. Betty's frustrations lead her to seek some new relief.
The staff at Sterling Cooper pull an all-nighter as they watch the Nixon-Kennedy election returns; Pete's ambitions cause him to directly challenge Don; Harry makes an impulsive decision.