The gang travels to a remote town to stay at the La Serena Spa, to relax Shaggy after a scary experience in a haunted mansion. There, they meet Mr. Hubley who works there. Shaggy asks if there is anything to eat, and Hubley says no, but there is a barbecue in town.
The gang goes to the barbecue, and all but Shaggy and Scooby-Doo go off to see the paleontological dig of Professor Svankmajer. Shaggy and Scooby are too full to walk right away. When they set out, a gila monster steals a biscuit from them, causing Scooby to go after it. He meets the Phantosaur (described as resembling an Appalachiosaurus by Professor Svankmajer) and runs away. Later, Shaggy and Scooby are chased by the Phantosaur and narrowly escape.