The gang from Mystery, Inc. is riding high as the focus of the first exhibition at the new Coolsonian Criminology Museum. But just as Fred (Freddie Prinze, Jr.), Daphne (Sarah Michelle Gellar), Velma (Linda Cardellini), Shaggy (Matthew Lillard), and their canine companion Scooby Doo are basking in the spotlight, their past comes back to haunt them--literally. Suddenly, the villains that the team has unmasked in the past have returned. This time around, a monster machine is producing Captain Cutler's Ghost, the 10,000 Volt Ghost, the Pterodactyl Ghost, Miner 49er, and others. But who is behind this dastardly deed