It opens on a beach on a Fourth of July night. LEAH (16), a bottle-blonde clad in a patriotic bikini with a cell phone in her hand, is chased by a SHADOWY FIGURE. She runs toward a bonfire as she tries to warn DARNELL (17), a young Black man. As Leah and Darnell meet, Leah collapses. The one Shadowy Figure is joined by other Shadowy Figures, as they surround the two teens.
Flashback to earlier in the day: Leah, now with bright pink hair, lounges on the front lawn. Her mother, BRIANNE (38), with a blonde bob cut and dressed in an American Flag shirt, yells at her neighbor about enforcing neighborhood rules. This gets eyerolls from Leah, who points out her mother's Karen-ish ways.
Darnell, who is Leah's boyfriend, arrives. It's clear that Brianne doesn't like Darnell. Darnell invites Leah to a bonfire on the beach. Brianne says that it's not burning season, so bonfires are illegal. Darnell shrugs, which pisses Brianne off even more. Leah says she can't go anyway. She doesn't have any beachwear.
This give Brianne an idea.
Brianne allows Leah to go. She even gives her a swimsuit: the patriotic bikini from earlier. It fits Leah like a glove. Leah realizes that she'll be eaten alive by mosquitos in that outfit, so she decides to put her clothes back on over the bikini and head to the drugstore for insect repellant.
At the drugstore, Leah finds that all of the insect repellant is out. She asks the clerk if there's any more. He says that it's all out. Leah, who's hair has turned a little more blonde and a little shorter, demands to speak to the manager. A Black Woman customer points out Leah's Karenish behavior. Leah echoes something her mother said earlier, to her disgust.
Leah runs out of the drugstore, only to be greeted by Brianne and a large group of white women in flag-related clothing. Each woman has a blonde bob cut. Brianne informs Leah that she's becoming one of them: a Karen. She insinuates that they're on the way to report the bonfire. Leah leaves, trying to warn Darnell. As she goes, she tries to remove the bikini, but it can't be removed.
Back to the present:
Leah points her phone at Brianne like a knife, warning her to stay back. Brianne tells Leah that she's not going to do anything. Darnell notices that Leah is dialing 9-1-1 without trying. The operator answers. Leah struggles as her hand raises the phone to her ear. Leah fights against her own words as she reports Darnell to the police. She emphasizes that he's a Black man.
Darnell, horrified, runs away. Leah breaks down. Her hair shapes fully into a blonde bob as the Karen mob embrace her. Police sirens echo in the distance.