In 2018, our journalist narrator begins constructing the facts of the case of FOSTER DADE (16), a second-year transfer to the Kennedy School in New Jersey. The narrator arrived as a student at Kennedy seven months after Foster was expelled and heard the story of his drug sales and conflict with various students as a kind of legend.
Flashing back to 2008, Foster is the child of recently divorced parents, his father having been outed as gay and closeted. Wanting to get away from the tension at home, he asks his mother to send him to boarding school and he arrives at Kennedy. A year behind the social scene, Foster is relieved when JACK ALBRIGHT (16) invites him to hang out with his friends, where he meets ANNABETH WHITTAKER (16), with whom he is immediately infatuated. Foster feels uncomfortable around this group of cool kids and quickly retreats back to his room, where he smokes weed with his suitemate, JAE-HYUN AN (16).
Foster struggles in his early weeks at Kennedy, unsure how to relate to his ultra-wealthy classmates and generally insecure and eager to fit it. He experiences panic attacks and when he comes home for Thanksgiving break, his mother sends him to a psychiatrist who prescribes him Xanax, Lexapro, and Adderall for good measure. Back on campus, he and Annabeth bond over the side effects of anti-depressants. He begins using Adderall to counter the foggy effects of his Lexapro.
Annabeth invites Foster and Jack to her home and they spend the weekend drinking and taking drugs. While high, Foster and Annabeth’s briefly hold hands. Back on campus, one of the second-year boys comes out as gay, which leads to a spate of homophobic jokes. During Spring Break, Foster receives more Xanax and Adderall from his psychiatrist.
At a party that SOFI COHEN (16) throws at her parents’ Manhattan apartment, Foster hands out his Adderall as a party drug. Foster takes so much and drinks so much that he can’t remember the night. A couple of weeks later, Jack asks if Foster can sell Adderall to the lacrosse team; they want it as a performance enhancer. Soon, word gets out that Foster sells Adderall and he begins receiving messages and requests from people he hasn’t met. He doesn’t need the money, but he enjoys being needed.
At the last dance of the term, a “slutty” first-year girl takes Foster outside and tries to give him a blowjob, but he’s taken too much Adderall to get hard and after she asks if she can buy some from him. Later, Jack asks him to come by his room and they watch porn together, Jack asking if it would “be gay” if they masturbated together. They have a sexually charged moment and never talk about it again.
Home for summer break, Foster gets more Adderall – including the longer lasting Vyvanse – from his doctor. Jae invites him to Hong Kong, where his actor father is filming a movie. There, he and Jae do a lot of drugs, and Foster ends watching ALEXEI (20s) feeding Jae Oxycontin and having sex while Jae is barely conscious. Alexei tells Foster he can get him large quantities of Adderall and Xanax from China. Jae will serve as the intermediary. Foster agrees, as word has gotten out around campus that he’s selling.
Foster spends the rest of his time in Hong Kong drunk or high and when he returns, goes to visit Annabeth at her parents’ home in the Adirondacks. Swimming in Lake Placid, they share a kiss so brief that Foster isn’t sure really happened, but he thinks about it constantly. From there, he goes to see Jack in the Hamptons and he and Foster go to a party at an upperclassman’s house. He’s so drunk that he insults a girl he’s hooking up with and he and Jack leave in the morning in a cloud of shame. The next night, at another party, Foster keeps getting texts from people at other schools that heard that he’s selling drugs. PORTER ROTH (16) leads Foster down to the beach and they make out for a while. Annabeth disappears upstairs with Jack. By the next morning, de facto couples – Foster and Porter and Jack and Annabeth – have formed.
Back at school, Foster is approached by HANNAH PHELPS-BERKOWITZ (15), a day student who is struggling in her classes. She begins buying Adderall from Foster regularly. Foster continues to halfheartedly date Porter, often unable to get an erection because of his drug use. The first attempt at full, penetrative sex during Homecoming goes very badly, leaving Porter in tears. Meanwhile, Alexei regularly sends packages to Kennedy for Foster and his business keeps growing. He has hundreds of pills in a closet in his room and begins selling to other prep schools in the area.
Foster feels Jack and the others pulling away; they frequently call him gay or make fun of him. Jack only stops by his room to buy drugs. At a dance in Manhattan, Foster is extremely drunk and high when he goes out to comfort Annabeth, who has been fighting with Jack. She confides in him and misreading the moment, he tries to kiss her. Jack sees this and hits him, and Porter is devastated. Foster is fully excommunicated from the group.
A baggie of drugs is found in another dorm, alerting the staff to a potential problem on campus. Jack and others begin posting insults and homophobic jokes on Foster’s Facebook profile, or shouting “f*g**t” at him on campus. Jae is expelled for plagiarism and Foster’s interest in selling drugs wanes – he leaves messages in his inbox unread for weeks.
Some of these messages are from Hannah, who has become addicted to Adderall and desperately needs it. With Foster not selling, Hannah goes into withdrawal. She ends up naked on a train platform and throws herself in front of an oncoming train. Foster returns to him room one night and sees Jack on his laptop, claiming to be downloading some of Foster’s music.
Annabeth reaches out to Foster and begins a reconciliation. Studying together, she uses his laptop and forgets to lot out of her Facebook. Foster can’t help himself and looks at a group chat between her and three other girls, which spans years and is incredibly mean about virtually everyone on campus. He reads a conversation about a paper of Foster’s that Jack saw on Foster’s laptop – an essay for his English class in which he confessed his love for Annabeth and his discovery of his father’s homosexuality. Foster saves the thread to a flash drive and then heads to a storage closet with a drain to dispose of his drugs. In the closet, he sees Jack having sex with another boy.
Foster uses the all-school email privileges he has via the school newspaper and sends Annabeth’s thread out, which leads to expulsions. But Jack also emailed himself Foster’s records of his drug transactions and hands them over to the administration. Foster is expelled as the campus reels from the Mean Girl thread.
We return to the narrator, who is compiling this story as a journalistic project, though he admits he’s not sure what it all adds up to. We learn that Foster deleted his social media after leaving Kennedy and then died of a drug overdose in 2019.