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.

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!

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.

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.

Blue Falcon run into Fishface, a fishy villain who plans to blend dry the rich cargoes passing in and out of big city harbor.

Manyface, a villain of many disguises, used a sinister symphony to send Big City to sleep, stripping it clean.

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.

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!

The Queen Hornet steals a armoured car filled with money, leaving the heroes on a search for evidence of her crime.

The super pair meets Swamp Rat and Mudmouth, two evil swamp monsters determined to turn Big City into a swamp.

The daring duo meets the evil Eric Von Flick, a hack movie director who attempts to make a movie legend, the total destruction of Big City.

The awful ordeal with the head of the steel Ironface, bearing a rather bitter grudge, seeks revenge on Big City and kidnaps the district attorney.

The red vulture steals two of the world's most powerful super jet engines.

The Worm, the Queen Hornet, Lowbrow, Superthug and the Gimmick form an evil team known as the "Injustice League of America".

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.