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.

Don and Megan work out some of their issues, Roger and Pete butt heads, and Joan has a run-in with a house guest.

As Sterling Cooper Draper Pryce tries to build upon its current business, Peggy is given new responsibility. Don and Harry indulge a client. Betty contemplates her mortality after seeing a doctor.

Don has an encounter with someone from the past. Meanwhile, Roger increases Peggy's workload, and Joan comes to a momentous decision.

Lane attempts to land an account with Jaguar Cars, leading to a altercation with Pete. Pete and Trudy host a dinner party in the suburbs.

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.

Megan has second thoughts about her future at Sterling, Cooper, Draper, Pryce. Peggy lashes out when she's inadvertently put in the uncomfortable position of having to lie. Pete's effort to protect an acquaintance doesn't turn out quite like he expected.

Don attempts to regain his creative spark, but undermines a member of his staff while doing so. Roger pursues some new clients, and in the process, hurts Jane. Betty displays her pettiness when she reveals a distressing secret to Sally.

Harry finds himself in an uncomfortable position after reconnecting with Paul Kinsey who has joined the Hare Krishnas. Lane takes drastic and unethical measures to get out of financial trouble. Don spends an afternoon with Joan to get her mind off her marital problems.

Pete asks Joan to make a personal and moral sacrifice to ensure the company lands the Jaguar account. Don becomes furious after learning of the impact Megan's new profession will have on their life. Feeling unappreciated, Peggy attends lunch with Freddy Rumsen, who encourages her to make a move.

Lane's shameful secret comes to the surface with dire consequences. Don recaptures his hunger for success, and Sally experiences a major milestone.

Roger seeks to expand his affair with Megan's mother. Pete has a "last" encounter with Beth with lasting repercussions. Megan struggles to find acting work and asks for Don's help getting an audition. Peggy still seeks Don's approval.