 Fred s boss, Mr.Slate, gives him tickets to a charity masquerade ball in Bedrock. However, he do invite the Rubbles since the tickets are pricey. Wanting to rent a costume, he goes to the only costume shop in town, where an obnoxious and snooty owner tells his costumes are sold out except for a double person dinosaur costume. But Fred learns by accident who his boss and this annoying shopkeeper their disguises. Wanting to praise his boss and insult this pretentious costume renter, little he knows both have switch masks at the ball...