A hardworking and bright high-school senior, Leigh Ann (Katie Holmes) has her impending status as valedictorian jeopardized when her bitter history teacher, Mrs. Tingle (Helen Mirren), gives her a poor grade on a project. This antagonistic relationship quickly escalates until circumstances lead Leigh Ann and her friends Luke (Barry Watson) and Jo Lynn (Marisa Coughlan) to hold Tingle hostage in her home. As the conflict continues, it looks as if not everyone will make it out alive.