Shortly before he departs for California with his children, Don tells Faye that he's experiencing a "sick feeling in the pit of my stomach." Faye suggests that resolving his past might ease his anxiety, and the two kiss. "I'm gonna miss you," says Don.
At the office, Lane promotes Joan to Director of Agency Operations, though with no boost in pay. "Well, it's almost an honor," she comments.
Meeting with the board of the American Cancer Society, Don proposes an anti-smoking campaign targeting teenagers that would employ sentimental imagery to tap into their unconscious fear of death.
Back at the office, Pete, Roger and Don ask Ken to exploit his future father-in-law's connection to a cancer society board member to help the agency land Dow Chemical. Fearing that doing so would jeopardize his marriage, Ken refuses.
In Ossining, Carla reluctantly permits Glen to say goodbye to Sally before the Francis family moves out. Betty discovers him in the house and fires Carla.
Don and his accountant are discussing the sale of Anna Draper's house and the Ossining home when Betty calls to say that Carla won't be watching the kids in California. Betty refuses Don's request to rehire Carla for the trip.
Joyce, meanwhile, introduces Peggy to a model who was fired from a Topaz Panti-hose shoot -- along with the ad agency producing it.
Megan schedules babysitters for Don, but he finds the arrangements unwieldy and offers to double Megan's salary if she'll accompany him to California. She accepts.
Ken tells Peggy that the head of Topaz, impressed that Ken knew the company had fired its agency, is giving Sterling Cooper Draper Pryce a shot at the account.
In California, Don returns to his hotel room after an exhausting day of meetings and marvels as Sally and Bobby recite a French lullaby Megan taught them. "You're like Maria von Trapp," Don tells her.
The next day Don visits Anna's house, where Sally notices the inscription "Dick + Anna '64" on the wall. "That's my nickname sometimes," Don explains. Stephanie hands Don Anna's engagement ring from the real Don Draper, which she wanted him to have.
That evening, Don and the kids plan the next day's Disneyland excursion while Megan heads to a nightclub with an old college friend.
At home, Henry questions Betty's judgment in firing Carla. "I wanted a fresh start," Betty says. "There is no fresh start," Henry snaps. "Lives carry on."
Don hears Megan return from her night out and knocks on her hotel room door. Don kisses her. "Are you sure we should be doing this?" Megan asks.
Back in Rye, Betty lies alone on Sally's stripped mattress.
After they have sex, Don asks if Megan thought this might happen when he invited her to California. Right away, she confesses. Don remarks that Megan doesn't know anything about him. "You have a good heart," she answers, "and I know that you're always trying to be better."
Don tells Megan he needs to know that they are beginning something more significant than a tryst; she assures him he has no reason to be afraid.
In New York with Ken, Peggy pitches concepts to two Topaz executives and receives a positive response.
Arguing with Bobby at a restaurant, Sally knocks over a milkshake. Don flashes with anger, then watches admiringly as Megan handles the mishap without scolding the children.
Back in New York, Megan wakes in Don's apartment. "I feel like myself when I'm with you," Don tells her. He asks Megan to marry him. She excitedly accepts, and Don slips Anna's ring on her finger.
Don summons Roger, Lane, Pete and Joan into his office and announces the engagement. "She makes me very happy," he says. Megan enters the room to applause.
Ken tells Peggy that he signed Topaz, and the two head to Don's office, where his engagement upstages their news. Privately, Don tells Peggy that Megan has "the same spark" she does, and that Megan admires her "as much as I do."
Megan reports that Faye has called again, and advises Don that waiting to tell her won't make the task any easier.
Peggy visits Joan and complains that Don's engagement overshadowed her role in signing the first new client since losing Lucky Strike. Joan mentions her unremarked promotion and explains she's learned to not get all her satisfaction from work. "That's bulls---," Peggy retorts, and the two laugh.
Don finally informs Faye about his upcoming marriage. Tearful, Faye says that she hopes his fiancée knows he only likes "the beginnings of things."
On the phone, Joan gossips with Greg about Don "smiling like a fool, like he was the first man who married his secretary." Greg asks when she's going to disclose her own news: she's pregnant.
Don visits the near-empty Ossining house to meet with his real-estate agent, but finds Betty there. The two reminisce about moving into the house, and Betty admits that "things aren't perfect" at her new home. Betty is taken aback when Don tells her about his engagement, but congratulates him as she hands over the Ossining key.
Later in his apartment, Megan sleeps as Don lies awake, staring out the window.