Scooby and the gang lose their cool--and their stellar reputation--when an anonymous masked villain wreaks mayhem on the city of Coolsville with a monster machine that re-creates classic Mystery Inc. foes like: The Pterodactyl Ghost, The Black Knight and The 10,000 Volt Ghost. Under pressure from relentless reporter Heather Jasper-Howe and the terrified citizens of Coolsville, the gang launches an investigation into the mysterious monster outbreak that leaves Shaggy and Scooby questioning their roles in Mystery Inc. The ever-ravenous duo, determined to prove they're great detectives, don a series of far-out disguises in their search for clues. Meanwhile, brainy Velma becomes smitten with a key suspect, Coolsonian Museum curator Patrick Wisely, as macho leader Fred and image-conscious Daphne attempt to determine the identity of the Evil Masked Figure who is unleashing the monsters in an attempt to take over Coolsville.