Hello Mary Lou: Prom Night II

Hello Mary Lou Prom Night II is a 1987 film, the second installment in the Prom Night saga. It introduced the killer ghost Mary Lou Maloney, who returned in 1989s Prom Night III The Last Kiss.

Later, at the 1957 prom at Hamilton High School, Mary Lou is attending with rich Billy Nordham who gives her a ring with her initials on it. Shortly after receiving Billys ring, Mary Lou sends him off to get punch while she sneaks backstage with Buddy Cooper, where the two are found making out by Billy. Storming off after Mary Lou claims she used him, Billy, while in the washroom, overhears two boys preparing a stink bomb and, when the boys abandon the bomb in the trash due to a teacher approaching, Billy grabs it. When Mary Lou is crowned prom queen, Billy, having snuck up onto the catwalk, drops the bomb on her before she is crowned. To the horror of Billy and everyone in attendance, the fuse of the bomb ignites Mary Lous dress and she dies after going up in flames, but not before seeing that Billy is the one who killed her.Thirty years later, high school student Vicki Carpenter Wendy Lyon goes looking for a prom dress in the school prop room after being denied a new dress by her overly religious mother. While searching, Vicki finds an old trunk containing Mary Lous prom queen accessories her cape, sash, ring and crown and takes them, releasing Mary Lous Hellbound spirit. After Vicki leaves Mary Lous clothes in the art room after school, Vickis friend Jess Browning Beth Gondek finds them and, after wedging a jewel out of the crown, is attacked by an unseen force and hung from a light by Mary Lous cape. Jesss death is deemed a suicide caused by her despair over her recent discovery that she was pregnant. ........

Source: Wikipedia