Pete returns home from his honeymoon excited about his new marriage but conflicted about his past encounter with Peggy.

Don Draper is shaken when his past life comes back to haunt him. After his picture appears in a local newspaper, Adam Whitman, a man who claims to be his younger brother, approaches him. Don, or Dick as his brother knows him, initially denies everything but in the end admits to having taken on a new name. He refuses however to have anything to do with him and tries to buy his silence. When one of the ad men gets a short story published, Pete Campbell is frustrated that his own stories have yet to see the light of day. When his wife approaches an old beau to see if he will publish the stories, he has an interesting proposition for her.

The Agency is looking to land an advertising contract to promote tourism to Israel. Don and his team try to come up with a theme but know so little about the country that they're stumped. So Don calls Rachel Menken to see if she has any ideas. Roger Sterling is getting tired of sneaking around with Joan Holloway and suggests she should get her own apartment but she knows better. Peggy comes up with an advertising concept during a testing session for a new line of lipsticks and she's subsequently asked to write copy.

Election night arrives and the staff of Sterling Cooper has a party while watching the returns. The election is close and it's obviously going to be a long night. Now a senior partner in the firm, Don Draper must hire a new head of account services, a post that Pete Campbell yearns for. Aware of Draper's secret past, he tries to strong-arm him into giving him the job. With his secret out, Don panics and he asks Rachel Menken to run away with him. Regaining his composure, Don calls Pete's bluff leading to a confrontation with Bert Cooper.

Don and Betty try to keep up appearances as they go to Betty's parents after her dad has a stroke. Peter has a long-dreaded meeting with his mother before he and Kinsey leave for a convention in Los Angeles.

Don is brought in to save the day for a P.R. campaign involving the building of the new Madison Square Garden, only to have the rug pulled out from under him. At home, Betty argues with her brother over how to care for their sick father.

Roger Sterling throws an expensive party with his new wife, Joan throws a dinner party, Peggy and Paul get stoned while working on an ad campaign, and Don's daughter Sally steals money from her grandpa.

Don has reservations about a misguided potential client who wants to sell jai alai as the "new national pastime." Meanwhile, Sal produces the "Patio" television commercial, Peggy searches for a roommate, and Betty's father passes away.

Betty has hallucinations of her deceased father as she delivers her baby, Peter considers trying to sell the untapped "Negro market" to a reluctant client, and Peggy begins to question her future at Sterling Cooper.

The bosses come in from London to reorganize Sterling Cooper, but a key player's career is sidetracked by a freak accident. Meanwhile, as Joan prepares to leave her job, her husband gives her some bad news.

As Don secures an account with Conrad Hilton, Sterling and Cooper try to strong-arm Don into signing a contract. Meanwhile, Betty meets with her acquaintance from the governor's office, and Duck tries to get Peggy to leave Sterling Cooper.

Betty tries to meet with Henry Francis again, while Don steps up his pursuit of his daughter's former teacher. At the office, Don disappoints Conrad Hilton and is forced by a client to fire Salvatore over an unwelcome advance.

As Sterling Cooper prepares for its 40th anniversary party, the bosses in London drop a bombshell to Lane. Miss Farrell's troubled brother pays a visit to her and Don, and Betty stumbles onto her husband's secrets.

An old flame and potential client reenters Roger Sterling's life, Joan's husband searches for a new job, and Don finally comes clean to Betty about his true identity.

On the weekend of the John F. Kennedy assassination, Pete finds out that he lost the promotion to Cosgrove, Roger Sterling's daughter's wedding goes off as planned, and Betty musters up the courage to respond to Don's confessions.

With another sale on the horizon, Sterling, Cooper, and Draper convince Lane Pryce to fire them and then join them as they start up a new advertising firm. At home, Betty follows through with her plans to divorce Don.

The new firm is struggling for business, so Peter and Peggy resort to a cheap publicity stunt to lure a client. Meanwhile, Don's personal problems and an unflattering newspaper interview puts his and the firm's image in jeopardy.

Freddy returns with a valuable new client, the firm reluctantly throws a Christmas party for its most important client, and Don prepares for his first Christmas away from his children.

Don flies to Los Angeles to visit Anna before his New Year's vacation to Acapulco, but her bad news influences him to cancel his vacation and return to New York, where he discovers that Lane has problems of his own.

Peter finds out that he will become a father, and has to break some bad business news to his father-in-law. Meanwhile an office focus group study for a client has some unintended personal consequences for Don.