July 1976. Susan and Bruce Miller are moving their suburban family lives just a few blocks away, but the difference is enormous. Their new neighbors, the Deckers, who have an open marriage and throw elaborate parties for other open-minded souls, mark a sharp contrast from their old neighborhood friends, the Thompsons. Also affected are the Miller children. Laurie has a stoner boyfriend but fancies her teacher more, and B.J. meets the mysterious girl next door.
After their first experiment with swinging at the Deckers' party the Millers decide not to make it a habit. Susan makes friends with Trina, while her old friend Janet distances herself from her. Bruce is successful at his new job as a stockbroker, and it turns into a celebration with the Deckers at the local Playboy club. B.J. helps the girl next door with her runaway plans while his sister Laurie accepts her teacher's invitation to see a play.
Concerned about her husband's desire for other women, Susan takes her family to church. To reach out to Janet she asks her to organize a housewarming party for them, and it becomes a true duel between old and new, between Janet and Trina. B.J. and Rick are punished for selling off Bruce's adult mags for cash, and Laurie joins a book drive to get closer to her teacher, Doug.
When the Thompsons cancel on the Millers at last minute, the Deckers join them on a weekend trip instead. When the Thompsons turn up anyway it spells disaster, but things turn for the better after Trina spikes Janet's brownies with pot. Laurie invites Doug over for dinner, but he regrets the kiss they shared last week. B.J. and Rick spend the day with Samantha, and they end up spending the night by the Deckers' pool.
Susan and Janet throw a Tupperware party, but on the other side of the road Trina Decker is preparing a more titillating kind of party: a benefit to cover legal expenses for Harry Reems, the star of the porn flick Deep Throat. This causes a stir in the Miller household. Logan confronts Laurie about her relationship with Mr. Stephens.
While Tom Decker has started working long-distance flights to Japan, Trina reestablishes her connection with her high-school sweetheart. Bruce asks Susan to join a benefit committee run by his boss's wife, and she brings along Janet. Hoping to be able to socialize in higher circles, Janet encourages Roger to demand a raise at work. While the boys go away on camp, Laurie finishes summer school ready to finally turn things serious with Doug.
In the middle of a heatwave, Tom and Trina are having a relationship crisis because Tom has slept with a girl he works with. Bruce helps his colleague Melinda learn the stockbroker trade, but will it turn into more than business? Janet finds out Roger lost his job, but Roger turns to Susan for comfort. Laurie is spending the summer with Doug, but learns that he has a job offer at her school.
Tom and Trina throw their annual Puzzlerama party: All their neighbors - and the Thompsons - are split into teams who have to solve clues and collect hidden tokens. The day brings revelations: Janet learns about a secret that her husband and her best friend have been keeping, Melinda makes sure she has Bruce all to herself, and Susan bumps into Laurie with the much older Doug, both gathering votes for the Carter campaign.
Bruce confesses to Susan that he and Melinda have been seeing each other. Rather than distance herself from him, Susan suggests they go to the Pendulum Club with Brad and Sylvia; The Deckers and the Thompsons join them. Laurie invites Doug over that night, and they're surprised when they see Laurie's parents come home early with Brad and Sylvia as company. B.J. and Sam hang out with Rick, but conflict arises over a game of spin-the-bottle.
Bruce sets up a trip to get his family back on track, but it's less pleasant than he'd hoped. Rick comes along, but he and B.J. fight about Sam. When Laurie hitchhikes back to town to be with Doug, her parents have to confront the reality of their daughter's relationship. Tom and Trina explore the delights of monogamy to reestablish the trust between them, and Janet takes Roger to see a psychiatrist because she thinks he's in a crisis, but ends up taking a session of her own.
Susan and Bruce decide to spend some quality time together, but end up going to a disco club with Tom and Trina. Janet starts her secretary job while Roger tries to help out around the house. Meanwhile, Roger puts a name to his feelings for Susan. Laurie spends her days with Doug, but looks for help from her father in studying for her driver's license. B.J. and Rick go on a double date with Sam and her cousin.
Susan throws a surprise birthday party for Janet while trying to handle her feelings about Roger's kiss. Bruce rediscovers his affection for Melinda. Janet is considering a career as an advice columnist while Roger is offered a job in Cincinnati. Laurie confronts Doug about their future together, B.J. hears unexpected news about Sam, and Rick decides to get wasted.
Roger announces he has accepted the job in Cincinnati, but Janet has had her advice column printed in the paper and has second thoughts about moving away. Trina considers her options regarding her pregnancy, but finally decides to share the news with Tom. A friend of Doug's is missing in an earthquake zone in Guatemala, and Laurie wants to join Doug in going to help in the relief effort. B.J. says his goodbyes to Sam while Sam's mother battles the thought of going to rehab. Susan confronts Melinda about her relationship with Bruce, but also faces up to her own ...