Hello Mary Lou: Prom Night II is a 1987 Canadian supernatural slasher film directed by Bruce Pittman, written by Ron Oliver, and starring Michael Ironside, Wendy Lyon, Louis Ferreira, and Lisa Schrage. It follows a high school student who becomes possessed by Mary Lou Maloney, a student who died at her high school prom in 1957. A sequel to the slasher film Prom Night (1980), it was originally intended to be a standalone film titled The Haunting of Hamilton High, but was retitled in order to capitalize on the success of the original Prom Night. The only story connection between the two films is that they are set at the same high school. Both films were executive produced by Peter R. Simpson.

Plot

In 1957, at a high school senior prom, student Billy Nordham discovers his date Mary Lou Maloney making out with another boy named Buddy Cooper. Mary Lou breaks up with Billy and infuriates him when she reveals that she was just using him. Shortly after, Mary Lou is announced prom queen, and Billy, looking for revenge, throws a stink bomb onto the stage as a prank. However, the fuse of the bomb accidentally ignites Mary Lou's dress, and she burns to death in front of the horrified students, but not before looking up and seeing who was responsible.