A scientist can't find 3 microscopic screws. Meanwhile, his daughter's boyfriend wants to steal the scientist's blueprints to gain personal benefit. When Chapulín finds out, he tells the man the story of Fausto and his pact with the Devil.
A dangerous criminal known as Tripa Seca escapes from prison and hides inside a house. Outside, a couple claims their baby is inside with the criminal. Now Chapulín must figure a way to get inside the house and save the baby.
