Naomi Roth arrives home with her five-year-old son, Teddy, to find that their automatic garage door won’t open. She sees the lights on inside, signaling that her husband, Jeremy Roth, is home from work early, which is unusual. She takes Teddy to the front door, which is locked, and her key no longer works in what appears to be a brand-new lock. After she bangs on the door, Jeremy opens it. He greets Teddy lovingly but sends him upstairs to play. Instead of answering Naomi’s question about the lock, Jeremy avoids eye contact and tells her that they need to talk, leaving her with the sense that something is very wrong.

Jeremy tells Naomi that he has a surprise: a complete home renovation, which he presents as a belated anniversary gift. He has already packed three large suitcases for her and asks her to go to his deceased parents’ dusty apartment nearby to clean it. He explains that he and Teddy will join her the following day and that they’ll all stay there during the renovation. Naomi is suspicious of his story, questioning why the locks were changed and why he packed so many of her things for what is supposedly a temporary stay.

Naomi drives to the filthy apartment and struggles to move the heavy suitcases Jeremy packed. Inside, she finds that he has packed an illogical amount of her belongings for a short trip, including a winter coat, even though it’s April, and her old medical textbooks. Her suspicion growing, she texts Jeremy to ask if he’s hiding something.

The next day, after cleaning the apartment, Naomi picks Teddy up from kindergarten. She tells her friends Ashlyn and Cheryl that they’re staying in an apartment during a home renovation. However, Teddy reveals that Jeremy never mentioned a renovation to him, making her friends suspicious. At the school, Naomi also notices Cora Janzen, a divorced mother who’s socially isolated by the other parents.

Naomi takes Teddy back to the new apartment, where he complains about the small space. Jeremy arrives soon after, still in his work suit and carrying only his briefcase, with none of Teddy’s promised belongings. He uses a pre-arranged code phrase, telling Teddy to go to the bedroom and “watch monkey videos” (37), which signals to their son that he must leave the room without question for a serious adult conversation. The code has only been used once before, when the family was informed of Jeremy’s mother’s death, signaling the gravity of the situation to Naomi.

Jeremy confesses that there is no renovation; he wants a divorce, claiming that he’s been unhappy for a long time. He admits that he tricked her into moving out to make the separation easier for himself. Though he denies that there’s another woman, Naomi doesn’t quite believe him. Jeremy insists that Teddy continue to live in the main house to maintain a stable routine. Believing that she can still save her marriage if she sees Jeremy regularly, Naomi agrees to the arrangement.

Naomi receives an email from Jeremy’s lawyer, Leonard Hardwick, asking her to put her lawyer in touch. She considers replying that they will reconcile but doesn’t send the message. She then speaks with her mother, Lorraine Paxson, who has been divorced three times. Lorraine is certain that Jeremy is lying about not having an affair and scolds Naomi for leaving the house, calling it a major strategic mistake.

Nearly a week later, Naomi continues to maintain the renovation story with her friends. Her deception is undermined when Teddy loudly asks about the difference between his father’s house and her new home, making Ashlyn and Cheryl suspicious. In the car, Teddy reports that a classmate whose parents separated got a “horse,” and he reveals that Jeremy told him they would now be living apart permanently. When questioned, Teddy confirms that only their nanny and housekeeper, Rosita, has been to the house.

When she shops for toys to decorate Teddy’s new room, Naomi’s credit cards are declined. She discovers that Jeremy has emptied their joint bank account, leaving only $25. When she calls him, he states that since they’re separating, she needs her own finances. He suggests that she restart her medical practice. He becomes angry when she resists, pressures her to get a lawyer, and hangs up on her.

After receiving a second, more threatening email from Jeremy’s lawyer, Naomi drives to the house late at night, intending to talk to Jeremy. She parks down the street and is stunned to see an unfamiliar beige Jetta parked in the driveway. Hiding outside, she watches as Jeremy escorts a beautiful, young woman with long, dark hair from the house and kisses her passionately on the front porch.

Naomi confronts Jeremy and the young woman, who introduces herself as Veronica. After Jeremy sends her away, he confesses to Naomi that he’s in love with Veronica, who is 28. He denies that he’s having a midlife crisis and insists that his feelings are genuine. Devastated but convinced that Veronica is manipulating Jeremy for his money, Naomi leaves, determined to uncover the truth and save her family.

Two days later, as Naomi waits with Ashlyn and Cheryl to pick up Teddy from school, a process server publicly serves her with divorce papers. Her friends gawk at her. Humiliated, Naomi tries to leave, but her son wants a playdate. Ashlyn pulls her son away, but Cora Janzen kindly steps in and invites Teddy to play with her son, Zack.

At the playground, Cora gives Naomi practical advice about her divorce. She reveals that Jeremy has hired the best lawyer on the island, Lenny Hardwick. She urges Naomi to hire a “shark” of her own to fight the prenup and protect her custody rights. Cora gives her the number for her own successful lawyer, Stefanie Gorman, and makes Naomi promise to call.

Naomi encounters Veronica at the supermarket and secretly follows her. After accidentally knocking over a large display of crackers, Naomi is confronted by Veronica, who condescendingly suggests that they should get along for the sake of “co-parenting Teddy.”

Enraged, Naomi tells Veronica that she’s just “eye candy” and that Jeremy will soon tire of her. Though Veronica claims to be in love with Jeremy, Naomi sees only cold calculation in her eyes and concludes that she’s lying. The encounter ends with Veronica making a veiled threat.

Naomi meets with Stefanie Gorman, the lawyer Cora recommended. Stefanie informs Naomi that she can’t take her case because Jeremy has already retained her, creating a conflict of interest. When Stefanie calls another top attorney on Naomi’s behalf, she discovers that Jeremy has retained that lawyer as well. Realizing that he has strategically blocked Naomi from hiring the best local representation, Stefanie refers her to a less conventional lawyer, Ezra Fletcher, and promises to call him on Naomi’s behalf to explain her difficult financial situation.

Naomi makes an appointment with Fletcher, though she feels uneasy about him. Later, she drops Teddy off at the house, planning to use the opportunity to speak with Jeremy. Her goal is to tell him about a threatening encounter she had with Veronica, hoping to plant a seed of doubt in his mind about her.

When she arrives, she’s met at the door by Rosita, who acts stiffly toward her. Rosita claims that Jeremy is working late, but her evasiveness makes Naomi suspect that he’s actually home. Rosita refuses to let Naomi inside and closes the door on her, foiling her plan to talk to Jeremy.

Naomi returns to her apartment to find the front door ajar. A search of the small unit reveals that nothing is missing, but she finds several things out of place: The shower curtain is closed when she normally leaves it open, and a knife from the kitchen block is sitting in the sink. Although she feels certain that someone was there, she decides against calling the police, worried that she’s overreacting and won’t be taken seriously.

Naomi meets with Ezra Fletcher in his rundown and disorganized office. Despite his disheveled appearance, he’s sharp and confident. He examines Naomi’s prenup, declaring it poorly written. He suggests that she signed it under coercion, a claim that Naomi denies, but he assures her it can be defeated. He senses her hesitation to proceed with the divorce but convinces her that she must fight to protect herself and her son from Jeremy’s aggressive tactics.

When Naomi arrives to pick up Teddy on Saturday morning, Jeremy is furious, claiming that she’s an hour late. Naomi insists that he told her to come at 10 o’clock, not nine. She then sees that Teddy is holding a new stuffed elephant, a gift from Veronica. Jeremy confirms that he has introduced them. When Naomi confronts him privately, he defends Veronica and dismisses Naomi’s account of being threatened at the supermarket, instead accusing Naomi of following and harassing Veronica. Naomi realizes that Jeremy will believe nothing negative about Veronica without proof.