A group of sorority girls are instructed to spend the night in a haunted house as an initiation. None of them believe in ghosts, and all expect their boyfriends to show up at midnight in an attempt to scare them with store-bought masks, so they relax in their pajamas and wait for the fun to start. Little do they suspect that the house also holds a secret laboratory where a mad scientist is performing nefarious experiments, turning beautiful girls into gorillas. The girls are abducted and chained in the basement, but luckily their boyfriends arrive in the nick of time and fight off the crazy doctor's henchmen (a werewolf, a gorilla, and a creature of some indeterminate type). Incensed at his monsters' failure to procure a girl for his experiments, the mad scientist instructs them to blast a hole in the movie screen with a laser gun and venture out into the audience. At this point the screen goes blank, and during Monsters Crash the Pajama Party's original theatrical run, actors wearing identical monster costumes would run through the crowd, chasing girls to bring back up onscreen with them. It's all played for laughs and both the comedy and horror is extremely lightweight, best enjoyed by fans of schlock cinema or anyone who feels nostalgic for the live "spook shows" that used to tour the country so many years ago.
by Fred Beldin synopsis