Don continues to conceal his complicated personal life, even in the face of Roger's invitation to open up.

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

Pete Campbell oversteps the mark when he pitches an idea for ad campaign to the head of Bethlehem Steel without telling Don Draper. Draper wants him fired but learns a lesson in corporate politics. Pete's wife wants to buy a Manhattan apartment but he has to approach his cold and distant parents for a loan. Pete's in-laws, however, are more forthcoming.

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.

When Don invites Roger home for dinner, too much alcohol fuels repercussions between Don and Betty and between Don and Roger. Joan puts Roger off for the weekend, spending time with her roommate Carol instead. Pete exchanges a wedding gift for a rifle, and then shares a hunting fantasy with Peggy. Bertram Cooper arranges for the Nixon campaign to meet with him, Roger, Don, and Pete.

Don is courted by Jim Hobart, head of a larger ad firm who offers him more money and more creative resources to join them. Betty Draper rekindles her interest in modeling after Hobart suggests she should try it. She doesn't realize it's all part of the strategy to get Don on board. Peggy Olsen is fretting over her weight gain but doesn't appreciate Joan's advice about getting ahead in the office. The ad team tries to counter the advertising coming out of the Kennedy campaign. Pete Campbell comes up with an idea to keep Kennedy's image off TV in key States.

Peggy is given the opportunity to write copy for a new weight loss device that everyone knows is useless. She finds an interesting use for it, however. Afraid of losing the Lucky Strike cigarette account, Bert Cooper gets Roger Sterling to come in for a one-hour meeting but he has another attack. Don Draper becomes a partner and takes over for his friend Roger, but some of the ad men are sharpening their resumes nonetheless. Pete Campbell wants a promotion but Draper doesn't seem too interested. Pete sneaks into Don's office and takes home a parcel sent by Adam addressed to Don that the mail room boy comes to deliver.

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.

On Valentine's Day, the staff of the Sterling Cooper Advertising Agency is hustling and checking out the newest office equipment. Don and Duck clash over an account, and Betty hears from an old friend.

Freddy and Ken take a client out to lunch who stirs Roger Sterling's heart.

Don and Duck try to bury the hatchet, and Peggy attempts to join in on the execs' after-hours meetings. Also, Duck receives a family visit at the office.

Betty becomes suspicious that Don is having an affair after her conversation with Jimmy Barrett, Joan helps out in the television department, and Peggy helps the church with a dance flyer.

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 accidentally learns a secret about Salvatore during a business trip to Baltimore. Back at the office, the firings continue, but the new management appoints Peter and Ken as new co-heads of accounts.

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.

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.

Don and Betty renew their love affair while on a business trip to Rome, while Peter has a bout of infidelity with an au pair in his building while his wife is away.

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.

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.

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.