While conducting a seance during a Halloween party, high-school seniors unlock the demon that remains locked in the crematorium.
Angela, the universe's most unpleasant party crasher, returns! Angela's sister, Mouse, is taken by her bullying Catholic school classmates to a party at Angela's favorite haunt, and before long, everybody's being turned into demons and only a butt-kickin' nun, who wields her ruler like a mighty sword of steel, can save the day.