The summer of 1976, the Miller family relocates to a more affluent neighborhood in the North Shore, a suburban area of Chicago. Bruce is a futures trader working his way up in the business, married to Susan. Susan is a homemaker who got pregnant and married Bruce in high school. The couple have a teenage daughter, Laurie, and a young son Bruce Junior, nicknamed B.J. Tom and Trina are their new neighbors. Tom, an airline pilot, met Trina while she was a stewardess. Tom and Trina quickly befriend Susan and Bruce, and they just as quickly learn that Tom and Trina have an open marriage. The move strains Susan and Bruce's friendship with Roger and Janet, their more conservative neighbors and friends from their old neighborhood. They try to maintain their friendship with the Susan and Bruce, but Roger and Janet are appalled when they learn about Tom and Trina's marital arrangement. Roger and Janet have a son, Rick. Although the show mostly focuses on the three couples, their children's stories are followed too, particularly Laurie, who is attracted to her summer school philosophy teacher Doug. B.J. and Rick's friendship is also tested by the move, and B.J. meets Samantha, an enigmatic girl who lives next door to him.