Don and Meagan are in Hawaii to experience the Sheraton Hotel and come up with an ad campaign. Don takes part in a wedding after meeting a soldier at the bar. Back home Betty tries to protect one of Sally's friends, Sandy, from living in the Village in an abandoned building. Peggy has to deal with a client who wants to pull an ad campaign at the last minute after events in Vietnam become a joke on the Tonight Show. Roger's mother dies and he has to deal with the funeral.
Don's affair increases in intensity while Meagan reveals that she miscarried. Herb from Jaguar returns to try and change the emphasis of the ad campaign. Heinz ketchup are interested in SCDP now that Heinz Beans are doing well again and when the news reaches Peggy she is asked to take a meeting. Pete's affair with a neighbour blows up in his face when Trudy finds out and warns him to do what she says or face a nasty divorce.
Harry wins important business from Dow Chemical and is furious when Joan fires his secretary. He bursts in on a partners meeting and demands to become one. Joan has an old friend to stay before she gets married. Meagan is given love scenes and tries to break it gently to Don. Don goes to dinner with the producer and his wife who suggest a little swinging. Don takes the meeting with Ketchup that he said he wouldn't do. He tries to keep it secret and is angry when Peggy's team show up for the same pitch.
Martin Luther King is assasinated during an Advertising Awards dinner. Henry has to rush to the Mayor's side and Don takes the kids into the city. He and Bobby go to watch 'Planet of the Apes.' Meanwhile Peggy is trying to buy an apartment, Ginsberg goes on a date and Pete is all alone.
Don goes to dinner with Herb from Jaguar and they part ways. At the same time Joan, Pete and Bert are negotiation with a bank to float the company. Roger leaps on an opportunity to chat up a Chevy executive at the airport and lands a meeting. Teddy Chaough gets the same opportunity and drunkenly kisses Peggy too. Pete runs into his father-in-law at a whore house.
The CGC employees move into the SCDP offices causing much upheaval. Sylvia has a big row with Arnie and calls Don to come meet her. He leaves her in a hotel room all day dependent on him. He returns to talk margarine with Teddy who can't drink the same amount as Don. Joan is in a lot of unexpected pain and Bob Benson ends up helping her. Pete is asked to look after his mother whose memory is failing her.
Chevy are asking for a pitch every week and the whole combined office is exhausted. Jim Cuttler calls in a Doctor to give them all shots to get them through the weekend. Chaos ensues as the office runs on amphetemines. Meanwhile Meagan leaves Sally in charge of her brothers while she goes out to a play.
Don and Betty take Bobby to Summer Camp and end up in bed together. He returns to Meagan to try and be more present while Betty returns happily to Henry. Meagan meets with her co-star and boss' wife who tries to comfort her. Pete meets with head-hunter Duck to discuss his options. Roger spends the day with his Grandson while Bob and Joan go to the beach.
Don and Roger head to LA for a meeting while Ted goes to meet the key man at Chevy. Joan thinks she is on a date but it turns out to be a meeting with Avon. Jim passes off Ginsberg and a meeting to Bob Benson.
Arnold and Don go out for a drink to talk about Arnold's son Mitchell who is being drafted to Vietnam. Don brings up the issue at drinks with Chevy much to Ted's discomfort. Pete becomes uncomfortable when his mother claims that she is having sex with Manolo the man Bob Benson recommended. Peggy is stuck in her apartment with a rat and has no one to help her.
Peggy and Ted are flirting more openly and get wrapped up in an ad for St Joseph's asprin. When the budget for the proposed ad expands rapidly Don intervenes. Meanwhile Ken gets shot by the silly Chevy execs and is more than happy to let Pete take his place. Pete is not happy to be working with Bob Benson though. He asks Duck to look into him and is surprised to learn that Bob is not who he says he is. Meanwhile Sally asks if she can attend boarding school. She has to spend the night to be observed and invites Glen over.
Don agrees to pitch to Hershey's but gets drunk when he's meant to be in a meeting with Sheraton. He ends up in jail after punching a man and decides he and Meagan should leave for California to handle the Sunkist account. Pete is shocked to learn his mother is missing at sea after going on a cruise with Manolo. He raves at Bob who then humiliates him at Chevy. Ted and Peggy sleep together and Ted says he will leave his wife. Joan invites Roger to spend Thanksgiving with her family.