The Daring Duo encounter the sinister Swamp Rat and Mudmouth, who've been hijacking trucks in the Bogmyer Swamp for the purpose of stealing their pumps. They use them to pump half of their swamp into Big City, turning it into Bog City, a giant swamp so muddy the citizens desert the city, leaving it unprotected and easy fair game for The Swamp Rat and Mudmouth. Blue Falcon and Dog Wonder, teamed with the Scooby Doo crimebusters, manage to extricate themselves from becoming gator bait and rush to the aid of the oozy Big City to lure the swampy thieves into the open. There, B.F., to allay Swamp Rat's suspicions, disguises Shaggy Rogers and Scooby-Doo as Blue Falcon and Dynomutt, respectively, and have them going the other way with the real Daring Duo posing as expensive gold statues at The Big City Convention Hall. The wily thieves, thinking B.F. and D.W. are heading elsewhere, feel free to steal the gold statues. When they learn of Blue Falcon's ruse, they flee into the swamp, only to be