In the SCDP elevator, Don coughs repeatedly. Megan steps away to keep her distance. The elevator stops and Andrea, a former colleague of Don's, steps in. She flirts until Don introduces Megan as his wife. "How many times is this going to happen?" Megan asks.
While Peggy, Ginsberg and Stan are working on the Topaz account, Joyce stops by with graphic photos from the Chicago nurse murders. Megan joins and looks while Joyce provides gory details. Ginsberg calls them "sickos" then storms out.
Joan and Gail prepare for Greg's return. Joan wants Kevin to be there when he arrives; Gail thinks he'll want to see Joan more than Kevin.
Sally calls Don at the office to complain about Henry's mother, Pauline, who is babysitting her while Betty and Henry are away. Don ends the call as Stan and Ginsberg arrive to go over a pitch for Butler Footwear. Don, still coughing, approves the pitch but asks about boards for a Cinderella concept. Stan reminds Don that he killed the idea because it was clichÃ©.
Upon his arrival, Greg kisses Joan then cradles Kevin. Gail offers to take the baby out for a bit. Joan and Greg retreat to the bedroom.
Back at the office, Don apologizes to Megan about the elevator incident. She expresses concern that Betty wasn't entirely to blame for his "careless appetite."
Sally reluctantly eats lunch while Pauline reads about the nurse murders. Sally leans over to read the newspaper but Pauline slaps her hand away. "Some things are not for children," Pauline says.
At the Harris residence, Greg tells Joan he'll be returning to Vietnam for another year. Joan accuses the Army of lying about his time commitment. "It's war," Greg says. "It doesn't stop for our plans."
At the Butler meeting, Ginsberg presents SCDP's pitch. The Butler executive approves the pitch and calls Ginsberg a genius. Ginsberg then launches into an impromptu pitch of the Cinderella concept, which the client favors. Later, at a bar, Don berates Ginsberg for presenting the Cinderella pitch. "Think of those ideas in front of me," he orders, leaving to make a call. "He's such a decent guy," says Ginsberg. Ken tells Ginsberg he almost got fired, but Ginsberg disagrees.
Don calls Megan then complies when she tells him to go home and rest.
Pete informs Roger that Mohawk wants to discuss a campaign on Monday morning. Roger says he'll be ready. He then asks Peggy devise a Mohawk campaign over the weekend. He offers ten dollars; Peggy requests all the cash he has on him -- $400.
At Don's apartment, Andrea stops by. He rebuffs her come-ons then sneaks her out via the service elevator.
Sally watches TV while Pauline chats on the phone about the nurse murders, but Pauline hangs up when she notices Sally eavesdropping. Pauline then recounts a story about her strict father to teach Sally a lesson about discipline.
Joan, Greg and Gail dine with Greg's parents; Greg's mother shares that Greg has volunteered for the extended duty.
While working late at the office, Peggy startles Dawn, who is asleep on Don's couch. Dawn explains that cabs won't go past 96th Street and her brother won't let her take the subway. Peggy invites Dawn to spend the night at her place.
A feverish Don awakens to find Andrea in his bedroom, which after some initial protests, leads to his unzipping her dress.
Sally reads about the nurse murders by flashlight under her covers.
Sharing beers in Peggy's living room, Dawn asks Peggy not to tell Don that she was sleeping in his office. Peggy reassures her, then talks about how copywriting is tough, especially for women.
At the Francis house, Sally tells Pauline she can't sleep because of the murder story. Pauline insists they're safe with her "burglar alarm" - a knife -- then gives Sally a sleeping pill.
Back at their apartment, Joan says to Greg about re-enlisting: "You can't make a decision like that without me." Greg storms out.
Handing Dawn a pillow and blanket, Peggy notices her purse on the coffee table and locks gazes with Dawn. Peggy leaves her purse on the table, collects the empty beer bottles, and walks out of the room.
Don tells Andrea their tryst was a mistake. "You loved it," she says. Don pushes her to the floor and chokes her until she goes limp. He pushes her body under the bed.
Betty and Henry arrive home to find Pauline asleep on the couch. Betty looks for Sally who is asleep under the couch.
Don wakes up to find Megan approaching with a breakfast tray. Andrea's body is gone. He asks Megan where she's been. She says she was with him all night and concerned about his health.
Joan tells Greg she wants him to leave and never come back. He says the Army makes him feel like a good man. "You never were," she says. "Even before we were married." He leaves.
Peggy finds the linens folded and a Thank You note from Dawn on the living room table.
Joan lies in bed with Kevin and her mother. A siren wails outside.