Gianna Greco, a seventh-grade reporter for the school paper the Eyeball, is struggling to find a compelling story in her boring town of Wolf’s Eye. On Monday morning, her bus makes an unexpected detour to The Pines, a seniors’ community. A group of elderly residents waits at the gate, fussing over a boy about Gianna’s age who boards carrying a briefcase. The new student wears ill-fitting, old-fashioned clothes that make him look like Gianna’s grandfather. Other students murmur insults.

Gianna sits next to the boy, who introduces himself as “Dex.” He explains why this is his first day attending school. When his grandmother registered him at The Pines, she listed his age as 60 instead of six to avoid paperwork. The county discovered the truth when its records showed that he had turned 65, prompting an investigation into a missing Social Security application. A truancy officer forced him to attend school.

During the ride, Gianna’s brother Ronny shoots a paper clip at Dexter’s neck. Gianna realizes that she’s found her story: whether a kid raised by seniors can survive middle school.

Ms. Napier, the guidance counselor at WEMS, greets arriving students. She spots Dexter Foreman immediately; he stands out due to his outdated clothes and bewildered expression. He stumbles on a missing stair in the 105-year-old building.

In her office, Dexter diagnoses water damage and insists that he was getting a great education at The Pines. Ms. Napier gives him his schedule and begins a tour, explaining the confusing room-numbering system. Dexter pockets two Sweet’N Low packets from her coffee service, reminding her of her 80-eight-year-old aunt Corinne, who also lives at The Pines.

In Dexter’s social studies class, the students hear knocking from inside. Dexter barges into Mr. Lam’s room, locates the problem radiator, and uses a quarter to bleed off steam, fixing the issue. Students call Dexter a “weirdo.” In the hall, Ms. Napier scolds him for interrupting class, but Dexter insists that he fixed the problem. The incident reminds her of her late uncle Louie, a handyman who could repair anything with simple tools.

Dexter reflects on how he once admired the school bus but now finds it gut-wrenching. Ronny has continued shooting paper clips at him. Outside school, Dexter confronts Ronny and drops his rubber band down a sewer grate. Ronny throws a punch, but Dexter ducks using self-defense techniques taught by Archie, a former bare-knuckle fighter. Students chant for a fight. When Ronny throws another punch, Dexter swerves, and Ronny’s fist slams into the bus. Dexter slips into the building and reports the injury to the nurse.

At The Pines, after being caught writing a letter to his friend Teagan, Dexter complains to Leo about the easy schoolwork. Leo explains that the school’s curriculum is designed for millions of students, whereas he could teach Dexter at his own pace. Leo encourages Dexter to use school to make genuine connections, dismissing Teagan as a long-distance crush. Other residents offer advice: Phyllis recalls sock hops, Cyril jokes about walking uphill to school both ways, and Archie suggests fighting the biggest guy in the cafeteria.

Because of his grandmother’s failing vision, Dexter reads her a newspaper article about potentially replacing WEMS. She tells Dexter to stop blaming the government like an old person and admits that they let his unusual upbringing go on too long. She suggests that his trouble adjusting stems from no longer being the center of attention. Dexter still refuses to accept that WEMS is where he belongs.

Jackson Sharpe scores the winning goal in a soccer game, but when he checks the math team tryout results, he finds that he came in second to Dexter Foreman, who scored a perfect paper. Jackson confronts the math team coach, Mr. St. John, suggesting a grading error, but Mr. St. John confirms that Dexter won fairly.

The next morning, Jackson sits next to Dexter on the bus. When Jackson introduces himself, expecting to be recognized for his soccer stardom, Dexter’s expression is blank. Jackson calls Dexter’s perfect score “pure luck,” but Dexter says that he never guesses at math and found the test easy. He explains that his previous teacher at The Pines was very challenging. Jackson asks who cuts Dexter’s hair; Dexter says that his grandmother does but that her macular degeneration is now making it difficult. Jackson suggests that Dexter quit the math team, but Dexter refuses, saying that his friend Leo would not want him to be a quitter.

In the Eyeball newsroom, editor Traci Vogel assigns Gianna a story about an electrician fixing the office laminator. Gianna protests, wanting to write about Dexter Foreman. She reflects on Dexter’s strangeness: He’s brilliant and aced the math team tryout, but he panics at the school bell.

Gianna intercepts Dexter outside a boys’ restroom and convinces him to walk to the cafeteria. They encounter Mr. Lam, who thanks Dexter for fixing the radiator and mentions the broken coffee maker in the teachers’ lounge. Dexter immediately heads there despite students being prohibited. He barges in and uses his Swiss Army knife to repair a broken wire. The teachers applaud when the machine works.

In the cafeteria, Ronny kicks Dexter’s lunch bag, scattering at least 15 individually wrapped items. Ronny mockingly calls Dexter a “geezer” and eats one of his candies, which turns out to be a “Nuclear Mouth Blaster” from Archie (63). Ronny’s face turns red, his eyes water, and he runs for a drinking fountain. Dexter smiles for the first time that Gianna has seen, showing that he can take pleasure in getting back at a bully.

The soccer team is 3-0 thanks to Jackson, but the math team’s 1-0 record is due to Dexter’s perfect score against Jefferson Middle School. Jackson resents that Dexter, who doesn’t even want to be at WEMS, outperforms him.

The next morning, Jackson complains to Sophie Tanaka, who lists his athletic achievements. Ronny claims that Dexter tried to poison him, but Sophie reminds him that he stole the spicy candy after kicking Dexter’s lunch. Jackson realizes that he needs to learn Dexter’s weaknesses.

That afternoon, Jackson sits with Dexter on the bus. Dexter explains that he’s not especially smart; he’s just ahead because his Pines teachers already covered the material. Jackson mutters that it’s too bad Dexter can’t return to The Pines, and Dexter agrees sadly. This gives Jackson an idea: If Dexter proves he’s too smart for WEMS, maybe they will move him to high school. At home, Jackson photoshops WEMS stationery and begins typing a letter to Dexter.