Don and Megan take a trip to Hawaii for the holidays, Sally's friend visits the Francis family, a comedian torpedoes Peggy's Super Bowl ad campaign, and Roger gets some bad news about his mother.

Don strikes up a friendship with the surgeon in his building, Peggy tries to save her campaign, Roger makes a scene at his mother's funeral, and Betty goes to Manhattan to find Sally's friend.

While Don continues his affair with Sylvia, Pete's latest infidelity threatens his marriage. Meanwhile, Peggy's icy relationship with her new staff continues, but she also gets an unlikely tip on a potential new client.

Don works in secret on a Heinz ketchup campaign while Megan gets a love scene on the set of her soap opera. Meanwhile, Harry makes his power play while Joan has more trouble with the secretaries.

Set among the events surrounding Martin Luther King's assassination, Peggy tries to get a new apartment, Ginsberg is set up on a date, and Don has a revelation during his weekend with the kids.

Things quickly become awkward after the two firms merge, Don asserts his dominance over Sylvia, Pete has to deal with his ailing mother, and Bob Benson helps out a sick Joan.

The creative department has a wild, drug-influenced weekend as they work on the Chevy account, Don has trouble letting go of Sylvia, and Sally walks in on an unwelcome intruder.

Don is preoccupied with keeping Sylvia's son from being drafted, Peggy has a rat in her apartment, Don and Ted bury the hatchet, Pete has a problem with his mother's new nurse, and Sally makes an accidental discovery about her father.

Roger gives Don some unwanted advice. Peggy and Stan disagree over an account's personnel. Harry asks for Don's blessing.