An edict from Roger and Lane puts Pete in a personal dilemma.

Peggy is forced to face some unpleasant facts about a client's discriminatory business practices. Don and Faye's burgeoning relationship is tested when Sally runs away from home and turns up at the office. Roger tries to rekindle his affair with Joan.

Sterling Cooper Draper Price employees resort to scuttlebutt after an agency wide meeting is called.

For the Draper family, life has changed. The children must adapt to a new home, a new brother, and a new stepmother. Don seems to have everything a man could want. However, Megan, still employed at the agency, has difficulty interpreting Don's expectations for a sex kitten at home and a prim and proper employee at the office.

Peggy has a tough time during a particularly formidable pitch. Don calls on a potential client. Roger and Jane have an experience with LSD.

Don is honored at a banquet for the American Cancer Society, but finds his professional reputation has been damaged. Sally lends a hand to a relative. Megan's parents come to visit from Canada.

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.

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.

As the firm prepares to go public, Don and Pete's actions cause them to lose two huge clients. However, Roger uses a new connection to put them in position to gain their biggest client ever.

Peggy becomes unsatisfied with her apartment and with Abe, Don has an eventful weekend with Betty while Megan has problems on the set, Roger has time with his grandson, and Pete begins exploring his options outside the firm.