Don's father-in-law pays a visit to his daughter's family. Peggy works hard on a campaign while the firm tries to decide if they will accommodate an unusual request from a client. Elsewhere, Roger plans a wedding.

The firm celebrates as they hit a milestone. Peggy and Paul compete to secure the same account.

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.

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.

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.

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.