Cory, a school mascot, is the best friend of the film's main protagonist, Alison Wentworth, who is a cheerleader. She has an introverted, miserable, shifty, sly, cunning, troubled, and dangerous personality. One by one, murders begin to take place at the cheerleader camp which they are staying at. At one point, Allison, her boyfriend Brent, and fellow camper Bonnie are confronted by rifle wielding janitor Pop, and Cory arrives and shoots him dead out of self-defense.
After returning to the camp, Cory has Brent go out in search of the missing Bonnie before rushing over to Allison, stating that Brent had to be the killer. She gives Allison her gun and tells her to be ready to use it as they go to confront Brent. When they find him standing over Bonnie's corpse, Allison shoots him dead in a panic before breaking down in tears. Cory was revealed as the true killer, however, when she fingered Allison as the killer when the police arrived, coldly stating that she might have been motivated by her low self-esteem. As Allison was taken away in an ambulance, coming to realize Cory's evil deeds, Cory is shown cheering her own name while donned in a cheerleading uniform and pom poms.
Despite her implied dissatisfaction with being the constantly mocked mascot and desire to be on top, Cory spends the majority of the film being passive and (deceivingly) kind to almost everyone. Additionally, Alison is equally nice to her, making the villainess's guiltless betrayal all the more sinister.