As Thanksgiving approaches, Don's work responsibilities interfere with his domestic life. Peggy is given a new opportunity, provoking the ire of some of her colleagues. Betty makes a startling discovery.

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.

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.

Pete (Vincent Kartheiser) returns from his honeymoon, excited about his new marriage, but conflicted about his past encounter with Peggy. After his business relationship with Rachel (Maggie Siff) takes an unforeseen turn, Don attends a party which further illuminates his increasing dissatisfaction with his present life.

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.

Michael Ausiello interviews Mad Men's January Jones.

The second chapter of Mad Men's Season 1 finale

The first chapter of Mad Men's Season 1 finale

The final chapter of Mad Men's Season 1 finale

Catch up on all the drama of MAD MEN's first season