When Clare arrives at Gabriel’s house, the mood between them is uncharacteristically awkward. Before Clare can speak, Gabriel tells her he thinks they should end their affair. He explains that he is worried someone will get hurt and that she has more to lose because she has a family. Although Clare had been considering ending the relationship herself, she is hurt by his preemption. She agrees to the breakup and leaves his house holding back tears.

Two weeks after the breakup, Clare finds Jed looking at photos of Sadie on her phone. She feels nervous, but he hasn’t found anything incriminating. Feeling restless and disconnected from her old life, Clare meets two friends from graduate school, Cassandra and Lev, for drinks. During their conversation, Lev mentions that Gabriel’s gallery, Prévost-Kline, is hosting a party nearby that evening. Emboldened by two martinis and a sense of recklessness, Clare agrees to go with them.

At the crowded gallery party, Clare spots Gabriel. The attraction between them is immediate, and he pushes through the crowd to greet her. He holds her close and asks her to leave with him. Clare tells her friends she is tired and meets Gabriel outside. They go to his nearby house and head straight to his bedroom, where the Blake Webley painting Longfin is hanging. As they begin to undress, they hear a thud from downstairs. Gabriel grabs a heavy Jean Arp bronze statue and goes to investigate.

After hearing a scuffle, Clare hides under the bed. A person wearing black Reebok sneakers enters the room; Clare knows it isn’t Gabriel, who was barefoot. After a soft scraping sound from the wall, the intruder leaves. When she emerges from hiding, she discovers that Longfin has been stolen.

Downstairs, Clare finds Gabriel’s body at the foot of the stairs; he is dead and covered in blood. She takes out her phone to call 911 but stops when she sees a photo of her daughter, Sadie, realizing an investigation will expose her affair and allow Dorothy to take her child. She wipes down any surfaces she touched and flees the house. She initially plans to find a pay phone to call anonymously but abandons even that plan as she rides uptown in a taxi, fully deciding to say nothing.

Clare returns to her apartment and goes straight to the bathroom, sitting on the closed toilet lid. Her husband, Jed, wakes briefly, and she lies about the time. Unable to sleep, she is haunted by the image of Gabriel’s body. She stays awake for hours until her grief gives way to tears. The next morning, Jed comments that she looks hungover. She maintains her lie, telling him she was home by 11 o’clock the previous night.

For the next day, Clare is consumed by panic and grief. As time passes without any news, she begins to wonder if she imagined the entire event. On Saturday morning, her reality is brutally confirmed when Jed reads a news article on his phone announcing that art dealer Gabriel’s death. Clare feigns shock and downplays her relationship with Gabriel, telling Jed they were merely professional colleagues. To establish an alibi, she mentions that she, Lev, and Cassandra briefly saw Gabriel at his gallery party on the night of the murder.

On Sunday, two NYPD detectives, Pam Breznick and Greg Nguyen, arrive at the apartment to question Clare about Gabriel’s death. Jed insists on being present during the interview and adopts a confrontational, lawyerly demeanor, instructing Clare not to answer detailed questions. When Clare mentions seeing Gabriel at the party on the night he died, Jed tries to silence her. He abruptly ends the interview, prompting Detective Breznick to ask what they’re hiding. After the police leave, Clare questions Jed’s aggressive tactics, but he insists he was just protecting them from unnecessary involvement.

The next day, Detectives Breznick and Nguyen intercept Clare after she drops Sadie at school. Breznick reveals they know about her affair with Gabriel and threatens to inform Jed unless she cooperates. Clare agrees to speak with them at a nearby diner. She resolves to admit to the affair but to maintain her alibi that she went straight home from the gallery party. 

Clare tells the detectives that Gabriel ended their relationship two weeks before his death. Breznick informs Clare that the murder does not appear to be a random robbery, as the killer used the correct door code and left valuables behind. The detective also notes that several witnesses saw Gabriel leave his own party early and asks whether Clare could be the reason. Breznick ends the interview by telling Clare that, as the married lover, she is a prime suspect and desperately needs to provide them with an alternative theory.

Reeling from the detectives’ accusation, Clare walks through the park. She calls her best friend, Maggie, and begins to confess to the affair, but in the middle of the call she has a flash of memory and realizes the killer stole the painting, Longfin. She abruptly hangs up on Maggie before disclosing that she was present at the murder scene. Clare understands that the theft provides the “other storyline” the police are looking for—a robbery gone wrong. However, she also realizes she cannot tell them. As a Blake Webley scholar writing her dissertation on Longfin, her knowledge of the theft would only make her look more guilty by proving she was there. Concluding that she is the only person who knows the painting is the key, Clare decides she must investigate the murder herself and starts by trying to identify the painting’s anonymous buyer.

Clare begins her investigation by calling Gabriel’s business partner, Michael Kline. Using her maiden name, Clare Regan, she poses as an art historian whom Gabriel had promised a viewing of Longfin. Kline is surprised the painting was still at Gabriel’s house and explains it was a private sale handled through Gabriel’s separate consulting business, so he has no information on the buyer. As the executor of Gabriel’s estate, he promises to look into it once the police release the crime scene. Clare then calls her friend Maggie back, explaining Dorothy’s blackmail threat and why she cannot tell Jed about the affair. She dismisses Maggie’s concerns and her offer to fly to New York for support, insisting she has a plan to handle the situation.

Clare attends Gabriel’s memorial service with Jed, who had insisted on coming despite her reluctance. The service is held at an arts center in Red Hook and is attended by many figures from the art world. Clare speaks with Tasha Wolfe, who confirms that the curator Clement Rosier initiated the deaccessioning of Longfin. Tasha suggests the museum needed the funds and that Clement likely already knew his friend Gabriel had a buyer lined up. Tasha and Clement both claim not to know the buyer’s identity.

Clare then approaches Gabriel’s ex-wife, Beatriz Barros, in the bathroom. Beatriz reveals that Gabriel had told her everything about his affair with Clare and that she was the one who gave Clare’s first name to the police. However, she denies any knowledge of the Longfin sale. Clare finds this suspicious, as it contradicts Beatriz’s claim that Gabriel told her everything. Clare spots the detectives, Breznick and Nguyen, at the service and avoids them before leaving with Jed.

The following day, Clare calls her friends Lev and Cassandra to ask about any art-world gossip surrounding Gabriel’s death, but they only have wild, unsubstantiated theories. Later, while Clare is at a playground with Sadie, she is approached by a tall, elegantly dressed woman she doesn’t recognize. The woman sits next to her on the bench and tells Clare she came to the playground specifically to see her.