Baron Greenback uses the minimizing peaka ray to shrink himself and his cronies and use the equally shrunken Frogs Head Flyer to enter the body of Colonel K. at the secret, secret service H.Q. Taking control of the Colonel's voice box, the villainous Toad relieves Dangermouse and Penfold from their duties. However, Professor Heinrich Von Squwawkencluck figures out the Baron's plan and shrinks DM and Penfold so they can enter the Colonel's nose, traveling in a conveniently shrunken Spacehopper.
Baron Greenback vows to blow up every single signpost in every country unless he is proclaimed emperor of the world. DM and Penfold set out for the Toad's secret island hideout somewhere in the pacific ocean.
Nine Top Secret cargo carrying ships have disappeared after encountering a ghost bus. DM finds the Ghost bus depot on a small island in the Indian Ocean where Baron Greenback is producing buses made of ice.
After half the world's most famous monuments have vanished, Dangermouse and Penfold head for America, where they find the Tower of London in the old west. It soon becomes apparent that Baron Greenback has invented a machine to shrink, transport and de-shrink objects (and heroes like Dangermouse).