Dynomutt

Willie the Weasel has created a formula that turns him into Mr. Hyde. While the Blue Falcon and Dynomutt are on the trail of the mysterious Mr. Hyde, they encounter the Mystery, Inc. gang and Scooby-Doo. Mystery, Inc. teams up with the Blue Falcon and Dynomutt (who happens to be Scooby's hero) to stop Mr. Hyde, who has threatened to turn the population of the entire city into "Mr. Hydes" unless he is proclaimed mayor

A caveman-like criminal named Lowbrow wants to become the King of Crime and steals some books that will help him in his quest. The Blue Falcon and Dynomutt end up assisted by Mystery, Inc. to stop Lowbrow.

The Gimmick is a criminal mastermind who uses his prowess of gadgets to create havoc in the city and dares the police to stop him from stealing a train car with a prince inside.

A talking worm called the Worm and his henchman Grub use a digging machine called the Wormborer to spring Bugsy Busby and Roto Chopper from prison in a plot to steal a super-computer.

A fish-themed villain named Fishface plans to steal Big City's oil and hold it for ransom.

Manyfaces uses his talent for disguises to trick Dynomutt into arresting the Blue Falcon, Mayor Gaunt, and the Chief of Police.

Superthug and his henchman Zorkon have created a super-dynamic steel skeleton and plan to use it to steal Big City's steel supply to mass-produce an army of steel skeletons.

The Blue Falcon loses his Falcon Communicator while he and Dynomutt are fighting Mr. Cool. Mr. Cool then makes the Blue Falcon think that he is F.O.C.U.S. One claiming that Dynomutt needs to be recalled to where he was made. With Dynomutt reprogrammed and now under his control, Mr. Cool has Dynomutt dispose of the Blue Falcon while he initiates a plot to freeze Big City.

The Blue Falcon and Dynomutt attempt to get evidence that will put the Queen Hornet in prison.

The Swamp Rat and his henchman Mudmouth plan to flood Big City by using stolen pumps to send half the water in Bogmeyer Swamp into Big City to start a crime spree. The Blue Falcon and Dynomutt, team-up once again with Scooby-Doo and Mystery, Inc. to stop the villains before Big City becomes Bog City.