The sinister villain, Manyfaces, is a master of disguise and he plans to use his talent along with a sinister symphony recording that puts people to sleep and create a fool proof crime wave. He first strikes at a symphony in which he disguises himself as the violinist and he puts everyone to sleep in the audience including Blue Falcon and Dynomutt. He then has his henchmen rob everyone in the audience.
Blue Falcon and Dynomutt are now determined to stop the next robbery and they figure that he will strike at the big basketball game in town and this time they are ready. Sure enough, Manyfaces and his cohorts strike and put the entire coliseum to sleep except Blue Falcon and Dynomutt, but Dynomutt malfunctions and the criminals escape.
Blue Falcon has a plan to capture Manyfaces and lures him out by driving an armored truck full of money with he, the mayor and chief of police in the truck and Dynomutt out front. They get Manyfaces to follow them to a barge but Dynomutt misses getting on the barge. While Dynomutt races to the bridge to jump on board, Manyfaces puts on a Blue Falcon disguise and captures the mayor and Chief Quimby. Dynomutt finds him and he tells him that the Blue Falcon at the front of the ship is Manyfaces and Dynomutt captures him, not knowing that he is the real Blue Falcon.
Dynomutt takes everyone to jail and Manyfaces begins a city wide crime spree robbing everything and everyone in sight after putting everyone to sleep. Blue Falcon convinces Dynomutt that he is the real Blue Falcon by pressing Dynomutt's one ticklish spot. They find the impostors still disguised as them and a chase ensues. Since Dynomutt is the only one that doesn't have a double and since he can't tell who's real and who's the phony, he captures all of them an takes them to the police station. There the fakes are unmasked and the crime spree is over.