When a horrible robot dog attacks the town, suspicion points to Scooby and the sheriff has him locked up. It is up to the gang to clear Scooby's good name, but standing in their way is a new enemy - a diabolical parrot named Professor Pericles who knows more about Mystery Inc. than he should. Add to this the growing friction between Shaggy, Velma, and Scooby, and you have a recipe for disaster.