When Jackie arrives home from the beach, she is startled by Morgan (M.K. Harris), a neighbor that thought she was having an open house, since her parents are selling their home. Morgan is very weird, adding to the range of suspects encountered by Jackie and her friends that day. The girls arrive that evening for the slumber party, and the fun starts immediately. While performing an amusing striptease, the girls are frightened by three of their male high school friends. Jackie and the girls are enraged by their joke, resulting in them being kicked out of the house.

Soon, one of the boys is violently killed by someone wearing a translucent mask, but the girls just dismiss the strange sounds they hear as a lame joke. Then, the weirdo from the beach frightens Jackie and Diane (Brandi Burkett) when they think it was one of the boys. Even though the stranger was only trying to return Jackie's address book she dropped, Jackie calls the police, but they don't take any actions in preventing it from happening again.

Ken arrives to the slumber party to see Juliette later on, but the fun quickly ends when Juliette is found dead by one of the girls after Ken leaves her alone in a bedroom. The terrorized guests don't know what to do and immediately suspect the weirdo or even Morgan for the killing. They attempt desperately at trying to inform the police, but they think it's a joke. What follows is a night filled with action-packed terror and suspense as the killer is revealed and the guests fight to survive.

Originally intended to be a separate film from the Slumber Party Massacre series, this is an enjoyable but unrelated follow-up. This time, you don't know who the killer is, but it's revealed pretty early on and the whole film is filled with exciting events leading up to the shocking end.