The following version of this novel was used to create the guide: Tate, Dizz. Brutes. Catapult, 2023.

In Falls Landing, Florida, a girl named Sammy Liu-Lou, the daughter of a prominent television preacher, mysteriously disappears. While the community, and particularly its church-going women, launches itself into a tizzy, a group of six children—Britney, Christian, Hazel, Isabel, Jody, and Leila—wander around the town and stir up trouble. The group of girls (plus Christian) have long been fascinated by Sammy and her friendship with a girl named Mia Halliday, slightly older than them, whose mother helps run an organization called Star Search that claims to be scouting for talent to send to Hollywood. Although the town is divided by a large white wall that surrounds the rich gated community which forms one half of it, the girls, who live outside the gates, have made a habit of peering over the wall in order to watch what Mia and Sammy are doing. After some time, the girls manage to track Mia to the basketball courts, where they find her having a tense conversation with Sammy's boyfriend and Christian's older brother, a boy named Eddie Suarez, before trying to make a romantic pass at him.

The girls begin reminiscing about the early days of Eddie and Sammy's relationship, a Romeo and Juliet affair in which Sammy would climb to the top of the wall and Eddie would help her down the other side with a ladder before taking her to the show home, an abandoned construction site that the girls and other children use as a hideout. Mia begins causing trouble around town; at one point, she scales the wall and pretends to jump off of it but in fact breaks her fall with a trampoline. During this period of time, Star Search begins holding auditions at the mall that are overseen by Mia's mother's boyfriend, a man named Stone, who encourages Mia to audition. The girls go to the mall to watch Mia perform, but she gives a presentation so awful that the girls suspect she has ruined it intentionally, even going so far as to fall off the stage at the end and run away crying. Meanwhile, several years in the future, an adult Hazel returns to Florida to visit Jody, who has become a conspiracy theorist and insists that there is a monster living in the Falls Landing lake.

While Hazel and Jody hunt for the lake monster, an adult Britney works as a server at a prominent art gallery and ruins the opening of her ex-boyfriend's exhibition, a tawdry installment with a leitmotif about doors. Years earlier, as children, the girls walk into the mall parking lot to find Mia crouched between the cars, laughing; she informs them that Eddie has been selected to go to Hollywood and responds positively when Leila steps forward to give her a kiss on the mouth. This kiss, and Mia's approval of it, sends a wedge through the friend group as the other girls realize that Leila has become extremely pretty and has managed to win the favor of the girl they have long obsessed over. The girls think back to a time from earlier in their childhood, when a baby wasp crawled into Sammy's ear and she made the news for telling her father that she was hearing "bad angels" in there. Meanwhile, in the present, the girls follow Leila and Mia down to the lake, where they begin kissing one another before Leila turns down an offer from Mia and Mia responds by shoving her into the water.

Although the girls are ready to let Leila drown because of her perceived betrayal, Eddie comes rushing to help her and drags her out of the lake, admonishing the other girls for their callousness. The girls then realize they have been standing on fire ant nests and rush into the water to soothe the stings, where they catch sight of a pair of yellow eyes looking at them under the surface; when they come back up, Mia tells Eddie that Sammy was cheating on him with her little brother, a strange kid who the girls know only as "lake boy." After Eddie leaves with Leila, Mia brings the girls inside the gated community, where her mother and her mother's friends grill them about Sammy's whereabouts and prompt the girls to run inside Mia's house to take shelter. Years later, an adult Leila becomes engaged to a millionaire but realizes upon returning to Florida and attempting to attend a motivational speech by "lake boy" that she has no interest in marrying him. At the same time, Isabel takes her two children to a theme park and catches sight of a woman whom she believes is Sammy Liu-Lou before showing her children a monster in one of the park's fish tanks, and Christian travels to Arizona to confront Mia about what occurred between her and the girls when they were children, and it becomes increasingly clear that Mia groomed the girls, resulting in their assault and exploitation by Stone, the leader of Star Search.

As children, inside Mia's house, the girls stumble upon lake boy's bedroom, where he demands to know what has happened to Sammy and claims to know her better than anyone in the world. The girls choose not to tell lake boy that they are hiding Sammy in a patch of woods called the wild place because she scaled the wall, asked for their help, and claimed to have something growing inside of her. After leaving, Mia brings the girls to Stone's house, where they are greeted by an Estonian woman named Elena who clearly seems to have been brought there against her will. The girls are eventually ushered upstairs, coerced into taking lewd photographs, and sexually assaulted by Stone. After escaping from Stone's house, the girls return to Sammy, who gives birth to a small stone which eventually transforms into a monster and jumps in the lake; meanwhile, the police search party hauls a deformed monster out of the lake before the lake bursts into flame.