It’s been 733 days since 16-year-old Jessie’s mom died, and about a month since Dad moved Jessie from Chicago to California to live with his new wife, Rachel. A week after starting at her new school, Jessie receives an email from an anonymous boy calling himself Somebody Nobody, or SN, offering to help her navigate Wood Valley. Jessie refuses. She wonders who he is and thinks through her first day. She must’ve appeared desperate; she embarrassed herself by admitting that she had spent her summer working. Then, a blond girl named Gem was the first person to speak to Jessie. She asked, “what are you looking at?”
A week later, in English class, a boy named Ethan asks Jessie to be his partner for their project on The Waste Land—but then informs her that he’s going to do the project alone and put her name on it. Dejected, Jessie texts her best friend from Chicago, Scarlett. Scarlett encourages Jessie to reach out to SN. SN is happy to help and tells Jessie to befriend Dri Sanchez. He also confirms that everyone is rich. Angry, Jessie decides that she can’t let Ethan do their Waste Land project alone.
When Rachel announces a family dinner, Jessie thinks back to her arrival in California. She thought Rachel’s house was beautiful, but it’s huge and pristinely white—and Mom isn’t there. Jessie is also sleeping in a guest room, which makes her feel like an interloper. At dinner, Dad announces that he got a job at a local pharmacy counter. Rachel’s son, Theo, is enraged, because he considers this job embarrassing. Later, Theo joins Jessie on the deck, rolls a joint, and says he smokes because his dad ran 12 miles a day and still died of lung cancer. He also shares that a kid died of a heroin overdose last year. That night, Jessie slips downstairs for tea, but she catches Dad and Rachel looking at a photo album on the couch. It makes Jessie feel like everything is broken.
At school, Jessie steels herself against Gem’s bullying, reaches out to Dri, and approaches Ethan about their English project. He agrees to work together. That night, Jessie and SN message back and forth. He’s at a party but insists it feels unimportant, unlike talking to Jessie. Things begin to look up when Jessie lands a job at Book Out Below!—a small bookstore owned by the mother of a Wood Valley senior, Liam. Jessie gets the job because Liam hits Jessie in the head with his guitar on accident and feels bad. Meanwhile, Jessie texts Scarlett and learns that Adam Kravitz asked Scarlett to homecoming. He’s the first person Jessie kissed, but she gives Scarlett her blessing. Jessie sits with Dri and her friend Agnes at lunch the next day. After Liam comes up to schedule work with Jessie, Dri shares that she’s madly in love with him. She makes Jessie promise to text her if Liam says anything cute. During Jessie’s training session, Liam mentions his band. Dri texts Jessie that Liam is part of Oville, a local band with some drama. When Liam invites Jessie to a party at Gem’s house, where the band is playing, Dri insists they have to go.
When Jessie meets Ethan to work on The Waste Land, she can’t ignore that she has a huge crush on him. They discuss The Waste Land as they walk; Ethan puts on his sunglasses and looks even more unreachable. He shares that he has most of the poem memorized, since he reads poetry when he can’t sleep. Later, as Jessie and SN text, they start a game in which they each share three things. SN’s third thing is that he likes Jessie. Jessie feels the same way, but she also feels weird—SN could be anyone. To earn Jessie’s trust, SN shares that his sister died a year ago. He admits that he counts the days, hours, and minutes since she died. At about the same time, Liam texts Jessie asking about work, Ethan texts Jessie about The Waste Land, and Scarlett texts Jessie a picture of her homecoming dress.
On Friday night, Jessie hangs out with Dri and Agnes. They discuss Agnes’s first time having sex. She had sex at theater camp just to get it over with, but her partner remembered halfway through that his religion forbade premarital sex. Agnes asks if the experience counts, and Jessie insists it does. Jessie confides in them about SN. When Jessie gets home, she joins Theo outside their parents’ bedroom and listens to them fight. When Rachel screams for Dad to leave and not come back, Jessie and Theo run away. They wonder if their parents will divorce, but Jessie finds that she doesn’t want that—she’d have to start all over again. Jessie is terrified that she and Dad will have to leave. While Jessie’s at work the next afternoon, Scarlett texts asking if she should have sex with Adam after homecoming. Jessie is shocked. Back at Rachel’s house, Jessie joins Dad on the deck but doesn’t ask about the fight. Dad nearly cries and says that his relationship with Mom was never hard. Jessie has no idea what’s going on. The next morning, SN admits that his mom abuses prescription drugs. Jessie meets up with Ethan after school and they go to Starbucks to work on their project. There, Jessie discovers that Ethan is also in Oville, and she’s confused when Ethan implies that he’s not a fan of Liam. That evening, Jessie and Theo share wine and Theo insists that their parents are dumb: they thought they could just replace their dead spouses.
Jessie heads to Gem’s mansion with Dri and Agnes for the party. Ethan ignores Jessie, but Liam drunkenly greets her. Right before the music starts, Dri says something cryptic about a kid named Xander dying and almost breaking up the band. After the first set, Liam returns to talk with Jessie, and Gem tries to get him away. Jessie sees a boy named Caleb texting at the same time as she gets a message from SN, which makes her think he’s SN. Gem returns to Jessie, calls her names, and tells her to leave Liam alone. In the morning, Jessie jokingly asks SN to visit her at work and heads downstairs. Dad tries to talk with her, but he’s shocked that Jessie would seriously think that his fight with Rachel means they’ll have to leave. At work, Caleb walks in. Jessie feels disoriented; Caleb doesn’t seem like he’d be SN, but clearly he is. She invites him to have coffee. Later, SN seems confused and as though he’s ignoring that he visited her earlier.
During Jessie’s next study session with Ethan, Ethan offers his condolences for Jessie’s mom. Jessie’s feelings for him grow. They also discuss Oville; Ethan notes that Caleb writes some of the band’s songs. Jessie wonders if the Oville boys all talk about her. All night, Jessie tries to make herself like Caleb since he’s SN, but she can only think about Ethan. The next day, Jessie reveals her crush to Dri and Agnes. Right after, as she walks into English class, Gem calls Jessie names and trips her in front of their teacher, Mrs. Pollack. After class, Mrs. Pollack asks Jessie if she did anything to provoke Gem and notes that since Gem’s dad is a major donor to the school, she can’t punish Gem. Jessie is ready to drive to Chicago when Liam catches her and asks her to work. Jessie realizes she can’t go anywhere. She still texts Scarlett and asks if she can move into Scarlett’s basement. Scarlett is thrilled, but says the couch down there is dirty—she and Adam have spent a lot of time there. Jessie ignores Dad’s texts asking to talk.
Giving Day rolls around. Jessie and Theo drive together to the Habitat for Humanity worksite and as soon as they get out of the car, Gem “runs into” Jessie. Theo calls her out and tells her to leave Jessie alone. Jessie tries to talk to Caleb but he ignores her after suggesting they have coffee on Thursday. When she later learns that Gem’s dad sponsored lunch, Ethan insists she has to eat and can’t give Gem the satisfaction of Jessie going hungry. On the drive home, Jessie thanks Theo for his help. He says that Gem has been horrible to him since they were little and tells Jessie a bit about his dad. He also warns Jessie that Ethan’s brother is into “heavy shit,” so Ethan might not be a good romantic partner. Jessie doesn’t care. When they get home, Jessie finds Rachel in her room. She’s angry about this until Rachel gives Jessie a plane ticket to Chicago for the weekend; Scarlett’s parents called, worried. Scarlett is thrilled and asks if they can hang out with Adam and throw a little party. Jessie is less excited about this, but agrees. Ethan agrees to move their Waste Land study session from Friday to Monday.
When Thursday rolls around, Jessie’s too nervous about her date to eat. Agnes isn’t convinced that Caleb is SN and at lunch, Dri notices that Gem and Liam aren’t sitting together. After school, Caleb cancels their date since Liam just broke up with Gem because of Jessie. Jessie is confused, especially when SN then texts her to celebrate her upcoming trip. She doesn’t want to tell him how much he hurt her feelings. On the plane, Jessie thinks about how good it’ll be to get Scarlett’s take on everything, but when Jessie arrives, Scarlett is angry and upset. She accuses Jessie of not listening at all since she left. The party that night is disastrous. Scarlett and Adam disappear, presumably to have sex, and Jessie messages SN while she’s drunk and calls him out on canceling their coffee date. She wakes up the next morning in Scarlett’s bed. Scarlett really just wants to talk about Adam—they haven’t had sex yet because Scarlett is too afraid, and Scarlett needs advice. Scarlett makes it clear that she does want to hear about Jessie’s life; she just needs Jessie to listen to her too. To demonstrate, she goes through Jessie’s new messages, in which Dri and Agnes confirm that Caleb’s sister is alive—he’s not SN. Scarlett thinks he’s Liam.
Jessie isn’t sure where home is as she takes off. Theo picks her up at the airport, curious to hear her take on everything, but she has nothing to say. Theo does share why Jessie shouldn’t date Ethan: his older brother Xander, the Oville singer, overdosed on heroin. Everything starts to make sense and Jessie starts to suspect that Ethan is SN. They plan to meet on Wednesday. On Monday, during Jessie and Ethan’s study session, Jessie offers Ethan her condolences for Xander. Ethan mentions that Liam is going to ask Jessie out. When she says she doesn’t want him to, he suggests she say no. On Tuesday morning, Theo talks Jessie into making up with Dad. Mrs. Pollack apologizes to Jessie for her poor handling of Gem’s bullying, and Dad stops in to visit Jessie at work. He apologizes for his bad behavior and tells Jessie mom would be proud of her. Scarlett also texts that she and Adam had sex and it went well. Jessie is thrilled. At Rachel’s house later, Rachel tells Jessie that she should decorate her room how she wants and apologizes for ignoring her. Jessie suggests they put out pictures of Theo’s dad.
The next day, Jessie waits at a restaurant to finally meet up with SN—but Liam, Ethan, and Caleb all show up. Jessie is confused until Ethan pulls out his phone, and she receives a text from SN. Ethan is SN. Liam is enraged, but he and Caleb leave. Jessie and Ethan sit, talk, and hold hands for several hours. Jessie feels at home in L.A. for the first time, especially when Ethan kisses her.