Mr. Hyde abetted by Hyde Dog, demands to be mayor of Big City, threatening its citizens with a sinister formula that turns them into evil Hyde-like creatures.
A Mexican vacation becomes a search for missing Aztec treasure for Scooby-Doo and the gang. The town of Cinco, supposed site of a gala fiesta, is deserted, what with its residents terrorized by a stone monster and the ghost of The Aztec God Of Contezuma. Searching for an ancient pyramid nearby, the gang find clues that lead them to a mysterious river barge and a cave where the treasure is being smuggled away.
Dog Wonder and B.F., teamed with the Scooby-Doo crimestoppers, meet Lowbrow, a villain desiring to be king of crime employing the knowledge from the books of Big City University to further his dastardly schemes. This primitive thief unwittingly leads Blue Falcon, Dynomutt and Scooby Doo and company to his lair, where they discover his latest plan: robbery of Big City Mint!
A visit to Ma and Pa Skillet in Okefenokee Swamp results in another adventure for Scooby and the gang. Cousins Scooby-Doo and Scooby-Dum greet each other for the first time since they were puppies. The Skillets own a showboat restaurant which specializes in Funky Fritters and Fenokee Fizz Soda and is being terrorized by The Gator Ghoul, an alligator-headed monster with glowing yellow eyes that has scared away customers and employees alike.
Dynomutt and Blue Falcon meet The Gimmick, a sinister crook using an assortment of mechanical devices to perpetrate a bizarre crime: the theft of the fabulous treasure of Price Ringpur of India.
In a mountain ski resort the Scooby-Doo Crimestoppers become involved with the mystery of The 10,000-Volt Ghost, who has been sabotaging the local power plant and turning the resort into a ghost town.
Blue Falcon and Dog Wonder encounter The Worm, an evil genius abetted by escaped convicts Bugsy Busby and helicopter thief Roto Chopper, seeking revenge against Big City. Swooping down on Big City Tech (scene of a freak accident years back when The Night Crawler, then Professor Ronald Hickman, was transmogrified from an intelligent scientist into a worm), The Blue Falcon and Dynomutt discover and try to stop the villains' attempt to pilfer a multimillion dollar computer. Despite a string of Dyno DumDums, The Daring Duo lure The Creepy Crawler and his even creepier cronies into a bizarre underground pursuit (where else would worms go?) and trick them into burrowing into Big City Prison.
Going to Niagara Falls the gang ends up staying at an asylum being haunted by the ghost of Dr. Coffin. His two henchmen seem to be driving an ambulance taking patients, but are they really patients or are they hiding something?
The superhero group are after a group of evil geniuses, Superthug and Zorkon. Superthug steals everything steel in the Big City to build a super dynamic steel skeleton.
While eating dinner,Scooby witnesses a burglary. A valuable coin was stolen by a No-Faced Zombie. As they follow the zombie to the Dilly Dally Dolly toy factory, they encounter a gorilla who might also be apart of the robbery.
In trying to combat the villainous Mr. Cool (a Mr. Freeze incarnate), whose cold rays freeze everyone into solid ice, The Blue Falcon accidentally drops his Falcon commumicator from his Falconbelt in trying to save Dog Wonder. Using the Falcon communicator device, Cool tricks B.F. into believeing he is Focus One, telling him Dynomutt is being recalled to the factory for a reprogramming. Dog Wonder is then programmed by Cool into an evil D.W., who nearly succeeds in ending Blue Falcon's career...and his life!
While the daring duo enjoy a leisurely game of golf, an evil genius known as "The Blimp", places his blimp lair high over Big City's head, messing with the city's supply of helium.
The prophet is predicting major disasters in Big City. Dynomutt and Blue Falcon are getting a bad reputation because they are unable to prevent the disasters.
