As the firm prepares to go public, Don and Pete's actions cause them to lose two huge clients. However, Roger uses a new connection to put them in position to gain their biggest client ever.

With his personal and professional life crumbling around him, Don positions himself for a change of scenery. Meanwhile, Pete's life is falling apart as well, thanks to the meddling of Bob Benson.

Don is on the outside looking in on the forced indefinite paid leave from his job. While Ted heads back to New York for a few days, Don takes the opportunity to head to Los Angeles in part to meet with a California transformed Pete while he reunites with Megan, who is living full time there while pursuing what looks to be a promising acting career. Back in New York, Peggy avoids Ted at all cost while she learns to deal with the new "Don", Lou Avery, most specifically on the Accutron account for which she is getting consulting help from Freddie Rumsen. On top of that, she is also having to deal with being a landlady to who she believes are overly demanding tenants. Ken feeling overworked leads to Joan taking over his scheduled business meeting with Wayne Barnes, the new Head of Marketing for Butler Footwear. Barnes' news results in Joan taking what she hopes will be seen as decisive and preemptive action in overcoming a potential problem, action which she hopes demonstrates that she deserves to be more than just a glorified secretary. And Roger meets with Margaret on her request, the two who have been somewhat estranged over the last few months. Their individual new approaches to life may result in a friction-free reunion.

Sally discovers that Don is not working, Pete lands a big account but is undercut by management, and Joan is forced to move some secretaries around after Lou and Peggy have some problems.

After a fight with Megan during a surprise trip to California, Don decides it's time to get back to work. Meanwhile, Betty joins Bobby on a field trip to a farm.

Don returns to work, but quickly falls off the wagon after learning that he's been assigned to Peggy. Meanwhile, Roger and his ex-wife go to a commune to rescue their daughter, who has abandoned her child.

While Lou becomes the object of ridicule for the copy writers, Don tries to get away to California after a call from his pregnant niece. Meanwhile, the new office computer drives Ginsberg to the brink of insanity.

Peggy has second thoughts about her Burger Chef campaign when Don is asked to pitch her commercial, Pete visits his wife and daughter on his trip back to New York, and Bob Benson gets some surprising news from G.M. about the account.

Don and Peggy prepare to pitch to Burger Chef, one day after the Apollo Moon Landing. Meanwhile, a power struggle in the firm between Sterling and Cutler leaves Don's future hanging in the balance.

Don decides to sell his apartment, Joan stumbles into a relationship while on a trip to Los Angeles, Glen tells Betty and Sally that he is going to Vietnam, and a copywriter gets in trouble for his rude behavior to a client.

The partners discover that the firm is losing its independence and there's nothing they can do about it. Peggy is not sure if she wants to come along. Meanwhile, Pete and Trudy have trouble getting their daughter into private school.