The gang from Mystery, Inc. is in Hawaii, and all Shaggy and Scooby-Doo can think about is going to a luau. But they're soon distracted by a scientist and his secret project - turning volcano soil into valuable gems! But when a spooky witch doctor starts haunting the volcano, Scooby-Doo, Shaggy, Daphne, Velma, and Fred are playing with fire. Can they save the gems? Or will the witch doctor get the gang first?