The film begins its journey in 1988, narrated by Lori Granger, who expresses her belief that her name is marked by a curse, suggesting that she is destined for either death or a life of violence. She ominously states that by the end of the night, she technically fulfills one of those predictions.
Two days prior, excitement fills the air at Shadyside High School as students prepare for prom night. Among the candidates for prom queen is Lori, who faces fierce competition from the popular and cruel Tiffany Falconer, her main tormentor. Tiffany is surrounded by her loyal friends, collectively called the "Wolfpack,” while the other contenders include Linda Harper (Ilan O’Driscoll), Debbie Winters (Rebecca Ablack), and Melissa McKendrick (Ella Rubin), who happens to be Tiffany’s devoted sidekick. Adding to the mix is Christy Renault, a rebellious local dealer who seems to be in the running just to annoy Vice Principal Dolores Brekenridge, who aspires for a better reputation for Shadyside.
In their classes, the girls gossip about the upcoming prom and their dreams for the future. Lori harbors aspirations of becoming a writer; however, the town's dismal reputation clouds her hopes. Tiffany and her clique take pleasure in bullying Lori over the dark rumor that her mother, Rosemary (Joanne Boland), is involved in her father's mysterious death. In a bid to stand up for her best friend, Megan Rogers, a self-proclaimed horror fan, performs a prank with a prop cleaver, which lands her in trouble with Tiffany’s father, Dan Falconer, who is also the teacher.
Throughout the day, Lori works as a waitress at a local establishment where Tiffany and her entourage taunt her. A seemingly mutual attraction develops between Lori and Tiffany’s boyfriend, Tyler Torres (David Iacono). Inside, Tiffany's vindictive personality is mirrored by her equally undesirable mother, Nancy Falconer. Meanwhile, as Christy completes a weed drop-off for some privileged students, she encounters a masked figure in a red cloak. The scene turns grim as the attacker fatally wounds her in a shocking turn of events.
As prom night approaches, the candidates gather for a rehearsal. On the way home, Lori is ambushed by Tiffany, who revels in the opportunity to demean her. Meanwhile, there’s a budding concern for Christy, whose absence becomes notable. As the evening unfurls, the masked killer methodically eliminates candidates one by one.
Prom night reveals more chaos when girls are separated and hunted. Linda and Bobby (Dakota Taylor) become one of the first victims, establishing a horrifying precedent for the evening. Tensions escalate as the killer starts to wreak havoc, leading to a shocking confrontation on stage. When Lori unexpectedly wins the crowning title of prom queen, her joy is short-lived as tragedy strikes, culminating in a frenzied showdown. Notably, Lori bravely takes a stand and uses her crown to combat the killer.
Ultimately, the night spirals into a chaos of betrayal, revealing that Dan has been orchestrating the mayhem for his wife and daughter's ambitions, ultimately leading to a deranged confrontation with Nancy. As the film draws to a close, true identities and twisted motivations surface with shocking revelations of the characters' dark pasts.
The credits roll as blood traces a chilling symbol, suggesting lingering ties to a malevolent family influence implied to shape the circumstances faced by the characters, leaving viewers pondering the consequences of their choices amidst chaos.
