A taboo office romance is revealed. At a brainstorming session, Peggy proves to be more than a secretary, opening up new opportunities for her at Sterling Cooper. Meanwhile, Rachel faces her conflicted feelings for Don after he seeks out her advice on a new campaign.

Don loses an account. Roger, stuck in the city for Labor Day weekend, attempts to cheer him up. Meanwhile, Joan has a night out on the town with her roommate.

On election night, the Sterling Cooper staff pulls a rowdy all-nighter while watching the returns. Pete's ambitions cause him to directly challenge Don. Don remembers his past as a soldier in the Korean War.

Peggy's family hosts a lunch for their church's new priest; Don and Betty enjoy a weekend together; Freddy and Ken take a client out to lunch; the staff works to prepare for a last minute pitch meeting.

Don buys a new car; Pete, Harry and Ken strategize to attract new business; Don's secretary makes a grave error; Cooper has a new piece of art in his office.

Freddy Rumsen disappoints his team during a pitch. Pete finds an opportunity at the office to exploit while Don proves his loyalty to an old friend. Betty finds a welcome distraction in Sara Beth.

Betty tries her hand at local politics. Don is forced into thinking about the future. Peggy receives a luxurious gift.

In the midst of a crisis, Don runs into an old friend.

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

Don renews his battle with Ted after seeing his relationship with Peggy, Sally interviews at a boarding school, and Pete discovers Bob Benson's background.