The Planet of Macaroni au Gratin, so called after its shape, was the next destination of the 999. Mane and Sab, the mechanical Dendorium brothers, who were bored with playing war games at the expense of the planet, captured (and shrunk) Maetel and Tetsuro so that they could escape the planet with the 999. They feigned a total war that destroyed the planet, but Queen Promethium (Maetel's mother) appeared and brought them to the train. Mother Computer Junior, discovered their escape and had them executed, while restoring Tetsuro and Maetel to their original size.
Main et Sab tuent le temps en se livrant à des jeux de guerre. Ils sont les dernières personnes vivantes sur cette planète où tout est contrôlé par l'ordinateur principal Junior. Mais, lassés de la guerre, ils complotent pour utiliser le 999 afin de s'échapper de la planète. Ayant besoin de deux personnes comme boucs émissaires pour tromper l'ordinateur principal Junior, ils choisissent Maetel et Tetsuro !
