A group of teenagers becomes the target of a relentless killer one year after accidentally hitting a man with their car and disposing of his body. The friends, led by Cindy Campbell and her boyfriend Bobby, try to get on with their lives, but they're all haunted by the incident and the mysterious messages they start receiving. As their high school's annual Halloween costume party approaches, the tension among them builds, with each suspecting the others might be responsible for the threatening letters.

The situation escalates when they begin to be killed off one by one in increasingly bizarre and violent ways. The remaining friends realize they must uncover the identity of their stalker if they have any hope of surviving. Their investigation leads them to suspect everyone around them, from the strange new student at school to Cindy's eccentric father. As the body count rises, the group's loyalty and trust in one another are pushed to the limit, setting the stage for revelations that could tear their friendships apart.