After her mom and friends are killed in a slumber party massacre, a high school girl is left as the lone survivor. She goes to live with her Aunt Katherine, who blames her for her sister’s death. Shortly after, she is witness to—and survives—another mass killing during a school field trip. Although she saves another kid’s life, others become wary of her. Believing herself cursed, she robs Aunt Katherine and skips town.
The girl, who doesn't reveal her name, struggles living on her own out of her car, without a high school diploma or a job. But she refuses to return home; Aunt Katherine wouldn’t take her back, and besides, she doesn’t want to get too close to new friends or guardians only to see them killed off as well.
She hears of another massacre at a frat house in a nearby town, and resolves to hunt down serial killers by staking out “popular” settings for massacres: drunken school parties, sleepy towns, etc. As the virgin “Final Girl,” she knows that she will be spared until she is the last one standing, so she can save at least some of the victims from the killer. To her, virginity is purely practical. It’s not a sign of self-restraint: she’s asexual.
At each massacre site, she asks those she has saved for spare cash in order to pay for gas, food, and other essentials. She tries to make few friends on her journey, knowing she won’t be able to stay anywhere too long.
She ends up in a small town back in her home state, California. She meets the town virgin, Joey, and her mom, Mrs. Norwood, who kindly invite her into their home, allowing her to shower and eat. But Mrs. Norwood is Black, and Joey is Black and Filipina—as the "Final Girl" explains to Joey and Mrs. Norwood, people of color are more likely to die, given the 80s-slasher rules of this world.
Joey’s friends arrive to surprise her for her birthday—meaning there are enough people present for a proper slaughterhouse. The Final Girl, Joey, and Mrs. Norwood survive the killers’ attacks, though Mrs. Norwood sustains serious injuries. After the massacre, the Final Girl gets drunk and tries to run away, not wanting to bring any more harm to the family, but Mrs. Norwood tracks her down, brings her back, and adopts her. They live happily and peacefully—though not without the occasional murder attempt.