A group of former high school classmates gather at their old school for a 10-year reunion organized by Lizzie Borden High School. As the graduates come together, they reminisce about their past and catch up on their lives. However, the event takes a dark turn when Walter Baylor, a former classmate who was institutionalized after suffering bullying and a traumatic yearbook incident, crashes the party. Disguised under layers of eccentric personas, Walter sets into motion a series of bizarre and deadly pranks aimed at everyone who wronged him in high school.

Unaware that Walter is the mastermind behind the increasingly strange events, the alumni must navigate the chaos that ensues. Amidst the confusion and comedy, the reunion becomes a battleground of bizarre occurrences, threats, and growing paranoia as the group tries to uncover who is responsible for the havoc. They are forced to confront their past misdeeds and reckon with their high school behaviors, all while trying to find a way out of the situation before it escalates further. The night becomes an unpredictable mix of humor, terror, and revelation as the group struggles to survive and make sense of the twisted turn their reunion has taken.