In the Headquarters of the T.I.A. (Terminal Intelligence Agency), someone has stolen Professor Bacterio's most dangerous invention, the D.O.T. (Demoralizer of Troops), an artifact that ends up in the hands of a very short, wacky dictator who is ready to use it for criminal purposes. The T.I.A Chief, though, is firm in his resolve: if he wants to get the D.O.T. back, he must NOT count on his agents Mortadelo & Filemon. But when the crime fighting duo discover that the T.I.A. has engaged a cocky and slimy detective from outside the agency, they decide to act at their own risk, even if that risk involves all of Humanity.

Wafer factory-owner P. Tinto and his wife Olivia want a child of their own more than anything else in the world. Years of trying, however, have left them with nothing but a pair of extraterrestrial midgets living in the spare bedroom. When they decide to try adoption, a series of misroutings and chance encounters results in an escaped adult mental patient arriving at their door with adoption papers in hand. P. Tinto and Olivia accept this without question and welcome him in as their son. Can this family arrangement work?