The movie opens with a heartfelt voice-over as a married couple, Adam Driver and Scarlett Johansson Barber, passionately describe all the reasons they fell in love, sharing a tender glimpse into their relationship. This intimate moment is part of an exercise suggested by a mediator, aimed at helping them navigate their impending divorce by focusing on positive memories, hoping to rekindle what once brought them together. However, when asked to read the letters they wrote to each other, Nicole, who used to be a well-known actress, becomes visibly angry and decides not to participate, storming out of the session. Nevertheless, the couple agrees to forgo legal battles, opting instead for a mediated divorce process, hoping that it will be less stressful—particularly for their young son, Henry, played by Azhy Robertson. They are living in New York City, where Charlie is a dedicated director of plays, and Nicole has starred in many of his productions.
Nicole is soon offered a TV pilot opportunity, which requires her to leave Charlie’s current play — right before it is set to transfer to Broadway — and head to Los Angeles. She decides to bring Henry along to stay at her mother, Sandra's house, played by Julie Hagerty. The move sparks tension, especially as a co-worker urges Nicole to get a divorce lawyer. She is eventually referred to Nora Fanshaw, played by Laura Dern, a formidable attorney who specializes in high-profile divorces. Nicole shares her story with Nora, revealing her feelings of insignificance in the relationship and her suspicion that Charlie, who had grown significantly as a playwright, might be unfaithful to her with his stage manager.
Meanwhile, Charlie sneaks away from rehearsals on breaks to see Henry, and during these visits, he shares with Nicole that he has received a MacArthur Genius Grant for his directing talents, a proud but bittersweet achievement amidst their crumbling marriage. Nicole, feeling increasingly sidelined, asks her sister, Anika Kash, to discreetly give Charlie the divorce papers. She does so awkwardly, leading to confusion for Charlie, who thought they were avoiding lawyers altogether.
Charlie soon encounters Jay, a sharp and aggressive divorce attorney with an exorbitant retainer, which intimidates him, prompting him to return to New York. There, he confides in his stage manager, Mary Ann, that despite their one-night stand, he can’t handle the emotional turmoil he’s facing. Nora contacts Charlie, warning him that if he doesn’t respond to the divorce papers within the specified period, the court may grant full custody to Nicole, given her request. In a frantic rush, he heads back to Los Angeles and begins meeting with various lawyers, only to find out that Nicole has already partnered with most of them, leaving him without many options.
Sandra offers a valuable tip about Bert Spitz, a seasoned entertainment lawyer who now works in a smaller practice. Charlie meets with Bert, who gently reminds him that because Henry was born and educated in California, the courts will see them as a California family—a serious complication for Charlie’s hopes of maintaining custody in New York. Charlie insists that their move to California was only temporary and argues that Henry should return with him to New York. Bert advises Charlie to rent an apartment in LA to strengthen his case, and his compassionate approach is a marked contrast to the aggressive tactics of Jay and Nora.
As Halloween arrives, Charlie takes Henry trick-or-treating again, despite Nicole already going with him earlier that day. Henry admits he likes California, a sign of his attachment to the city, but Charlie remains unsure. Nicole’s career begins to flourish as her show becomes successful, solidifying her intention to stay in Los Angeles. In court, Nora passionately argues that Charlie, who has continuously resisted the California custody plans, has neglected Nicole’s wishes and needs. Recognizing that Charlie has been uncooperative, Bert advises him to accept the California arrangement, warning that holding onto the hope of returning to New York might be futile. Charlie’s emotional state deteriorates and he is seen weeping, having been advised that he should let go of his native New York.
The legal battles intensify as Nora and Jay fight over assets, accusations of alcoholism, infidelity, and financial claims, turning the courtroom into a battleground of personal attacks. An independent evaluator is appointed to assess both parents, with Henry witnessing the tense and sometimes hostile exchanges. Nicole ventures to Charlie’s apartment, seeking a calm conversation, but it quickly devolves into a brutal argument. During the conflict, Charlie makes a reckless joke about a pocketknife, which turns dangerous when he accidentally injures himself, bleeding profusely—highlighting the chaos and emotional pain both are experiencing.
As negotiations finally settle, Charlie and Nicole reach an agreement, with both lawyers withdrawing their more extreme claims. Henry will remain in LA with Nicole, though a court detail reveals that Nicole has 55% custody while Charlie has 45%, a compromise driven by Nicole’s desire to keep peace. Later, Charlie visits a jazz bar in New York with his cast, where he sings “Being Alive”, symbolizing his complex feelings of loss and hope. The following Halloween, Nicole, now dating someone new and nominated for an Emmy for her directing work, meets Charlie at her house, happy and optimistic for their futures. Charlie reveals he has taken a directing job in LA and will be nearby, suggesting that their relationship, while changed, remains connected.
The film concludes with a poignant scene as Henry finds the letter Nicole wrote at the start of their divorce process, prompting Charlie to read it aloud through tears. As the night ends, Nicole softly asks Charlie if he wants to take Henry for the night, even though it’s her custody time. Charlie agrees, and as he leaves, Nicole runs after him to retie his untied shoe, sharing a quiet, meaningful moment that underscores their complex but enduring bond.
