Maltazard, the Evil M, is evolving and 7 feet tall among the humans, wherever he belongs, causing terror. His goal is straightforward: judgment over the universe and forming an army of giant henchmen. Meanwhile, Arthur is still a Minimoy, and thus in a country where he is unable to off him. With the assistance of both Selenia and Betameche, he hatches a plan to recover his typical size: all they need to do is Arthur's house through the pipeworks, grab an electric train out of his bedroom to his grandfather's study in order to find an elixir which will make him return to his human size. Though it weren't for Darkos hot on the tails, sounds simple enough.