In 1963, Rob Stanton, an engineer, and Beth Ann Stanton, a housewife, move into their Pasadena mansion following the death of their daughter. After meeting Leo and Sheila Mosconi, Beth Ann overhears Sheila reveal that Leo witnessed Rob kissing a waitress. Beth Ann refuses to believe her husband's infidelity until she sees Rob kiss the waitress firsthand. At Sheila's advice, Beth Ann goes to the diner to confront the waitress, who she learns is named April. However, Beth Ann loses her nerve and instead befriends April, although she keeps her identity secret.

In 1984, socialite Simone Grove lives in the mansion with Karl, her third husband of ten years who owns a successful art gallery. At a party, Simone learns of her husband's homosexuality when she finds pictures of Karl kissing a man. Simone demands that Karl leave, but Karl instead appears to attempt suicide by overdosing on pills. After Karl is sent to the hospital, Tommy Harte, the son of Simone's best friend Naomi, admits to Simone that he saw the photos and makes a romantic pass at her. While flattered, Simone declines his advances as he is just under the age of consent. Tommy leaves, but tells Simone he has been in love with her for years.

In 1963, April admits to Beth Ann that she's in a relationship with a married man, still unaware that he's Beth Ann's husband. After April suggests that the affair is the result of Rob becoming bored with his wife, Beth Ann attempts to make herself more appealing to Rob by updating her style and giving him a blowjob, but her efforts culminate with her accidentally injuring him. While waiting to be treated at the hospital, Rob acknowledges that he is growing distant from Beth Ann, but stops short of admitting his infidelity. Once treated for his injury, Rob leaves the mansion for an apparent dinner with business partners despite Beth Ann's attempts to make him stay, knowing that he is really meeting with April.

In 1984, Simone discovers that Karl faked his suicide attempt, but is unable to force him out of the mansion when Karl threatens to humiliate her by disclosing his homosexuality to her friends. Naomi Harte reveals to Simone that she has known about Karl's infidelity for over a year, although she is unaware of his sexual orientation. Feeling betrayed by Karl and Naomi, Simone begins an affair with Tommy, who is now a legal adult.

In 1963, when Beth Ann learns that Rob intends to meet with April in a nightclub to celebrate the completion of a project, she visits his office and takes the project files with her. Forced to remain in the office to recreate the project, Rob cancels his plans with April, who invites Beth Ann to go out with her. At the nightclub, April reveals to Beth Ann that she is not pursuing a serious relationship with Rob and has no intention of getting married, preferring to instead focus on becoming a singer.

In 1984, Simone and Karl are forced to attend a charity dinner together, with Tommy serving as their waiter. Tommy grows increasingly resentful towards Karl and his treatment of Simone, culminating in him intentionally spilling food on Karl and getting fired. Afterwards, Simone chastises Tommy for his behavior. Tommy questions the status of her relationship with Karl as they still seem friendly. Simone tells Tommy that while she fully intends to divorce Karl, she does not dislike him. Karl and Simone end the evening by tangoing at the charity dinner as Tommy looks on.

In 1963, April and Beth Ann go roller skating and afterwards eat brownies laced with marijuana. April admits that Rob has been doing marijuana for more excitement in his life. Beth Ann realizes she has forgotten about a dinner party at Rob's boss' home and will now have to go with Rob while high. She charms the hosts and fellow guests, but admits to Rob that she "knows what [he's] been doing". After the dinner, Rob asked how she knew about the marijuana, not knowing Beth Ann was actually referring to his infidelity. After Beth Ann does not answer, Rob tells her how he has forgotten how to enjoy life. They go rollerskating in their neighborhood and Rob starts to regain interest in Beth Ann.

In 1984, when Simone refuses to accept Tommy's gift, a sports watch, Tommy leaves her in the middle of their date. Later, Amy, Simone's engaged daughter, cancels her wedding with her fiance Brad due to a misunderstanding. Tommy agrees to go on a date with Amy to make Simone jealous. After listening to a speech on love made by Karl, Simone realizes her true feelings for Tommy. She then interrupts their date to reconcile Brad and Amy, and mends her relationship with Tommy by wearing the watch he gifted her.

In 1963, April auditions to sing at a local bar, and she gets the gig. April makes plans for Beth Ann and Rob to come watch her when she sings, but after Rob gets two tickets to the World Series, Rob declines April's offer. However, Beth Ann pretends to be sick and instead goes to the bar for April's performance. After, they go back to April's apartment. Rob shows up and Beth Ann is forced to hide in the bathroom. April then tells Rob that she is in love with him, but Rob starts yelling at her, saying he will never leave his wife, and he storms out.

In 1984, after Simone and Tommy get lost on the way to a motel, Simone asks for directions, but a police officer mistakes Simone for a prostitute, forcing them to explain their illicit affair and reconsider a different arrangement. When Naomi finds out Tommy's been leaving the house at all hours of the night, she signs him up for a housekeeping service to water neighbor's plants to keep him busy. When Simone hears this, they start meeting in the empty houses to have sex. However, when Joyce, Simone's neighbor, comes home early while they are having sex, Simone is forced to call Karl to help her out of the bedroom. Karl drives to their house and crashes into Naomi's car, creating a distraction for Simone to leave. Karl also discovers Simone has been having an affair with Tommy.

In 1963, Rob and Beth Ann throw a housewarming party to celebrate unpacking. Beth Ann goes around the neighborhood inviting all her neighbors, including Mary and Ralph Vlasin. Beth Ann describes their encounter to April, who strongly suspects that Ralph is hitting Mary. At the party, Mary and Rob dance, but a jealous Ralph pulls Mary into the study and starts yelling at her. Beth Ann intervenes and tells Ralph to leave, but after he storms out, Mary follows him. Rob and Beth Ann get into an argument about how Rob did nothing to stop Ralph. As a retort, Rob yells at Beth Ann saying that she wasn't a good mother. After Beth Ann finds out their neighbor Sheila overheard their fight, Beth Ann admits that she was the reason their daughter died.

In 1984, Simone and Karl go to dinner with Amy to meet Brad's family, after Amy discovers they are getting divorced she asks them to keep this to themselves as Brad's family is conservative. While at the restaurant, Simone sees Hector, her favorite stylist who seemingly dropped her as a client for no reason. Karl excuses himself from the table and is apparently hiding out from Brad's family. When Simone goes looking for him, she finds Karl and Hector making out in the men's bathroom and they return to the table. After Ruby, Brad's mother, starts asking questions about Simone's ex-husbands, an angry Simone tells the entire table that Karl is gay. Then, Karl tells Brad's family about Simone's affair with Tommy. Brad's family is shocked, and the dinner ends abruptly. Back at the mansion, Karl and Simone fight and Karl angrily admits he was in love with Hector but ended the relationship some time ago. Simone then visits Hector to talk about Karl's relationship with him.

In 1963, Rob dumps April after she said she loved him, but she learns that she's pregnant and he's the father. Beth Ann and Sheila discuss telling Rob about her knowing of the affair, but during the discussion, April appears in the driveway of the mansion. Sheila opens the door and pretends to be Beth Ann. Later, Beth Ann plans to tell Rob that she knows about the affair, but she stops herself. A worried Rob asks if she's sick, and Beth Ann then tells him that she has cancer.

In 1984, Simone tells Karl that she still wants to divorce him, but that she wants to part amicably. She invites Hector over and he and Karl go on a date. Tommy buys Simone a very expensive brooch, Naomi is alerted about the withdrawal and starts to think that Tommy is buying drugs. After learning the real cost of the brooch, Simone attempts to return it to Tommy while he's at track practice. Someone spots Simone but does not recognize her, and informs Naomi they saw Tommy with a suspicious person, leading Naomi to think Tommy is actually dealing drugs. Naomi breaks into Tommy's room to try and read his journal, but Simone goes to her house to try and stop her and successfully distracts Naomi by revealing that Karl is gay. Tommy invites Simone to travel to Europe with him. Though Simone initially declines, she agrees to think about it. Karl discovers he has AIDS, but doesn't tell Simone.

In 1963, Beth Ann and Sheila visit Sheila's nephew, a doctor who specializes in oncology, to talk about what kind of cancer she should say she has. After they land on epithelioid hemangioendothelioma, she tells Rob that she has six months to live. April misleads Beth Ann and has her drive her to an illegal abortion clinic. While there, Beth Ann becomes worried about April's safety and tells her about the death of her daughter Emily, and that April reminds Beth Ann of her. Convinced that April's death would devastate Beth Ann, April agrees to leave without getting the procedure. Beth Ann tells Sheila what happened and considers taking April's child to raise, as Rob loved being a father and Beth Ann couldn't have more children. Sheila chastises Beth Ann and cuts ties with her. April storms into Rob's office and tells Rob that she's pregnant, and Rob responds by proposing to her, saying that his marriage will be over in six months. April calls Beth Ann and tells her the news, when Beth Ann learns what has happened she faints in the middle of the street.

In 1984, Simone and Tommy discuss their vacation to Europe, and since he cannot afford the extravagant things Simone has in mind, she suggests that he sell the brooch and find a more creative way to show her that he cares. At a dinner party, a woman approaches Simone in the bathroom, saying she is Karl's doctor's wife and is also a nurse in his practice. She tells Simone that Karl has AIDS. After the party, Karl confirms his diagnosis. Simone decides to cancel her trip with Tommy in order to take care of Karl. Upset, Tommy steals a bottle of wine from Simone and drives away in his car, getting in an accident. At the hospital, Naomi finds Tommy has gotten a tattoo of Simone on his leg.

In 1963, while at the doctor with April, Beth Ann sees Mary, who has been visibly hurt. Beth Ann goes to Mary's house to check on her, and questions why she stays with Ralph. Mary admits that Ralph has a gun and threatened to shoot her if she leaves. After their talk, Beth Ann decides to leave Rob and goes to his office to say goodbye, but he isn't there. Rob's secretary Claire then tells her Rob has cheated with many women, including Claire. Claire admits that she was the reason Beth Ann's daughter Emily died; Claire went to their house to meet Rob, but after Beth Ann and Emily came home early, Claire fled out the back door and left it open, causing Emily to wander into the street. Rob knew the truth and has been gaslighting Beth Ann. Beth Ann changes her mind about leaving Rob, and forgives Claire on the condition that their conversation stay between them. On the way home, she buys a gun.

In 1984, Naomi spreads the rumor that Simone has been molesting Tommy for years and tells everyone that Karl is gay. This gets Simone and Karl kicked out of their country club. Naomi furiously shows up at the mansion and tells them she will do much worse, as she knows that Karl has contracted AIDS. When the news reaches Amy, she insists that Karl and Simone shouldn't come to the wedding. One day, Simone and Karl find that their house has been graffitied with slurs and Karl's diagnosis, drawing a crowd. Karl starts getting dizzy and almost faints, Simone pleads for help but their neighbors are reluctant to go near him due to his disease, and only their gardener is willing to help. At the hospital, Simone sees Naomi and pleads with her to leave Karl out of their feud. Naomi isn't satisfied, saying she will continue her tirade, but Tommy overhears her and angrily ends his relationship with his mother. An enraged Naomi gets in her car and waits for Simone to come out of the hospital, and when she does, Naomi drives into Simone.

In 1963, Beth Ann tells Rob she has bought a gun that she will keep loaded in the kitchen due to break-ins in the neighborhood, then initiates a scheme with Mary to cause their husbands to kill each other. Mary hides her belongings, then leaves a note for Ralph that she's having an affair with Rob and is leaving to be with him. Beth Ann plies Rob with alcohol and questions him about Emily's death, but Rob continues to deny his role in their daughter's death, encouraging Beth Ann to continue with their scheme. April arrives at the mansion suddenly, having learned the truth about Beth Ann's identity. Ralph arrives with his gun shortly afterwards and argues with Rob, prompting a struggle between the two. In the ensuing scuffle, Beth Ann removes the bullets from her gun before tossing it to Rob, ensuring that he's gunned down by Ralph. A decade later, Simone meets Beth Ann, who reveals that Ralph was executed for Rob's murder, and April has become a singer, with Beth Ann helping raise her and Rob's daughter Elsie. The three of them move to New York together so that April can appear on Broadway.

In 1984, Tommy saves Simone from his mother, resulting in Naomi being injured. News spreads of Naomi's actions and she is exiled by her society friends. Tommy offers to cancel his trip to Europe to be with Simone as she takes care of Karl, but Simone encourages him to travel and pursue new relationships. Six months later, Simone is forced to sell off her art collection to pay for Karl's medical bills after they lose their insurance. Karl starts stealing sleeping pills in an attempt to end his life as his condition worsens. Karl is discovered and Simone discards the pills, despite his pleas that he does not want to suffer a painful death. Seeing an AIDS victim take a turn for the worse convinces Simone to help Karl end his life without pain. The two share a final dance before Simone euthanizes her husband. Decades later, Taylor and Eli meet Simone, who has become a philanthropist active in AIDS research, while Tommy is revealed to have become a successful painter.