Following the overwhelming events of the Cuban Missile Crisis, Don Draper experiences recurrent flashbacks of his own birth that paint an image of his birth mother and her interactions with his father, as well as his bitter stepmother. Don and Sal continue to pursue their hidden lives, complete with bold sexual encounters and frequent trips for “business.” Pete’s promotion brings him only a temporary happiness, as he soon realizes the new deal comes with strings attached. To Don’s dismay, his wife Betty’s father moves in with them, and Betty names her newborn boy after him.
Joan thinks she’s finally quitting her job, but unexpected news from her husband forces her to reconsider. Don’s new relationship with hotel tycoon Conrad Hilton comes with many demands, and he struggles to meet them. Both Betty and Don get involved in affairs outside their marriage, and Peggy starts a sexual relationship with Duck. As complications arise, Don’s secret identity can no longer be kept in the dark, and his wife finds out the full story.
John F. Kennedy’s assassination affects many, and Betty can no longer tolerate her fading marriage, which leads her to ask for a divorce. The season wraps up with Don and Roger joining forces to star a new advertising agency.