A gypsy fortune teller warns Scooby and the gang not to visit Franken Castle. They go anyway and find themselves chased by a werewolf, a vampire and a Frankenstein Monster.
The gang travels to Salem to visit a friend, Arlene Wilcox, on Halloween night. However, the town is being haunted by a witch, and the townsfolk suspect Arlene, who is a descendant of the witch in question.