What begins as a relaxing spa getaway for Scooby-Doo, Shaggy, Fred, Velma and Daphne somehow takes a very strange turn when the gang uncovers a frightening Phantosaur, a ghostly dinosaur thats come to life to protect hidden treasures buried in secret desert caves. The Phantosaur appears to be on a mission to keep a group of paleontologists from digging for fossils. The gang sets out to investigate the prehistoric haunting and in the process uncover all sorts of colorful suspects including a free-wheeling motorcycle gang, greedy corporate investors and over-zealous scientists. Will it be prehistoric panic or will our teenage sleuths put all the pieces together and solve this strange mystery?