The novel opens with twenty-one-year-old Natalie Murphy calling her estranged father, Andrew, from a New York City police station. In a flat, emotionless voice, she tells him she has killed someone. The narrative then jumps back four months.
Nat is a struggling illustration student at the School of Visual Arts, living in a cramped Bushwick apartment with two resentful roommates. She grew up in Blaine, Washington. Her father abandoned the family when she was 10, relocating to Las Vegas, and her mother, Allana, remarried a builder named Derek Heppner. Nat is still haunted by her high school boyfriend, Cole Doberinsky, who grew obsessive after she ended things, eventually breaking into her family's home at night. Charges were never pressed due to his family's local influence.
Nat's classmate Ava Sedin, a fellow illustration student from a working-class background, invites Nat to her luxurious Chelsea penthouse and reveals that she is a sugar baby: She dates wealthy older men and receives monthly financial allowances. When Nat's finances collapse and she loses her bar job, she asks Ava for help entering the sugar-dating world. Ava gives her a makeover, coaches her on safety rules, and helps her create an online profile. Within an hour, Nat agrees to a five-hundred-dollar drink date with "Angeldaddy" without doing any background research.
The man is Gabe Turnmill, a 55-year-old corporate attorney. Chapters told from Gabe's perspective reveal he is still married to Celeste, a former public defender and breast cancer survivor who lives at their Sagaponack home in the Hamptons with their teenage daughter, Violet. Gabe lists himself as divorced on the dating site and uses his driver, Oleg, a Moldovan immigrant, to maintain discretion.
Nat's first date with Gabe is a disaster: She arrives drunk, blacks out, and wakes at home with no memory of the evening but finds five hundred dollars in her coat pocket. A second date with a different man goes wrong when he expects her to participate in a sexual fetish she did not understand. Humiliated but broke, Nat contacts Gabe again.
Their relationship deepens. When Nat's mother warns her that Cole has left Blaine and may be heading to New York, Gabe promises to protect her. After Nat spends the night at his apartment platonically, Oleg offers her a nine-millimeter pistol during the drive home. Nat hides the gun in her apartment. Gabe ends things with his previous sugar baby and proposes a formal arrangement: thirty-five hundred dollars per month in exchange for seeing each other twice a week. Nat accepts.
Ava is brutally assaulted by a sugar daddy she met through the site. Though shaken, Nat takes comfort in having Gabe as a steady partner. Shortly after, she spots Cole near campus, and he sends threatening texts. During a spring-break trip to Vermont, Nat shows the texts to Gabe, who writes down Cole's details and promises to handle the situation. That night, they have sex for the first time, and Nat realizes she is in love.
Cracks appear. At a Broadway show, Gabe silently warns Nat not to approach when he spots old friends, making clear he is ashamed to be seen with her. Cole's threats stop, and Nat assumes Gabe intervened. Ava defers from school and moves back to Ohio with her mother, warning Nat that sugar relationships are never real. Nat dismisses the warning. Then Cole appears at Nat's apartment door, severely beaten, and tells her Gabe's people nearly killed him. Nat is horrified but also relieved.
At Gabe's apartment, Nat discovers hidden family photos confirming his wife is very much present. The narrative shifts to Gabe's perspective: Celeste has revealed that Violet has been engaging in self-harm, afraid her parents will split up. Gabe, who had considered leaving Celeste for Nat, reverses course and recommits to his family. He gives Nat a diamond necklace and cash and tells her the arrangement is over.
Nat spirals into heavy drinking and obsessive behavior, leaving Gabe alternately pleading and threatening voicemails. An anonymous person publicly outs her as a sugar baby online, and her roommates discover the gun and evict her. Though the arrangement is over, Gabe sets Nat up in a Chelsea studio and pays the rent.
Consumed by anger, Nat tracks Violet's social media and follows her to the Metropolitan Museum of Art, where she strikes up a conversation. Over coffee, Violet reveals her parents are still together, confirming Gabe lied about being divorced. Nat cultivates the friendship and accepts an invitation to Violet's graduation pool party at the Hamptons estate. At the party, Gabe recognizes Nat with horror. After Violet's girlfriend throws punch in Nat's face, Gabe takes Nat upstairs to change, and their physical attraction nearly overwhelms them before Violet's footsteps interrupt. Violet later kisses Nat.
After the party, Gabe meets a handler at the Bronx Zoo and pays five thousand dollars to have Nat killed. Days later, during a walk on the High Line, an elevated public park in Manhattan, Nat threatens to spend time with Violet. Gabe tells her quietly that he will kill her. Nat screams obscenities and claws his wrist until it bleeds. Gabe calls the handler and orders the hit expedited to that night.
That evening, Nat goes drinking and notices a man with green eyes watching her. At a nightclub, someone drugs her drink. She stumbles home and wakes on her apartment floor, covered in vomit and blood. In the shower, a flash of memory surfaces: Gabe's terrified face and a gunshot. After sleeping for an indeterminate period, she is awakened by police and arrested for Gabe's murder.
The evidence is damning: her fingerprints on a Beretta found near the scene, the diamond necklace by the body, hundreds of threatening messages on Gabe's phone, and no alibi. Nat's father flies from Las Vegas, hires defense attorney Matthew Hawley, and posts bail. Oleg comes forward, revealing that Gabe hired someone to kill Nat. The prosecution offers a plea deal for second-degree manslaughter with a recommended two years. Nat accepts, believing she may have pulled the trigger.
At sentencing, Celeste delivers a victim-impact statement that stuns the courtroom. She calls Gabe a sociopath and says Nat's greatest crime was falling in love with a manipulative man. She asks for counseling rather than prison. Judge Amanda Wollner sentences Nat to one year plus probation, then suspends the sentence entirely. Nat returns to Blaine, enduring gossip and shame while caring for her younger siblings. Months later, Celeste visits and tells Nat firmly that she is not a murderer.
The final chapter, told from Celeste's perspective, reveals the truth. Celeste has known about Gabe's affairs for years. After the pool party, she tells Violet about Gabe's relationship with Natalie. Devastated, Violet drives to New York, breaks into Nat's apartment, and finds her father's tie on the pillow. After a night of drinking, Violet confirms Gabe's location at a jazz club, goes there, and shoots him in the face. Celeste instructs her to clean up and orchestrates a frame with Oleg and his cousin Max, the green-eyed man. Max drugs Nat at the nightclub, follows her home, and takes the pendant and gun from her apartment. He plants the pendant on Gabe's body and wraps the Beretta in a cranberry-stained T-shirt found in Gabe's car. The linchpin is a doctored ballistics report: Celeste's friend Manny Dosanjh, a firearms examiner in the New York City Police Department crime lab, falsifies his findings to match Nat's gun to the killing, though a different weapon was used. As Oleg drives Celeste home, she invites him to stay the night and feels, despite everything, a tentative hope.