Professor Crumhorn returns and uses his transformation pills to turn himself into a little girl in an attempt to get Danger Mouse to break into Fort Knox.
Just when Penfold should be meeting his Aunt and the airport, he and Danger Mouse are sent to the Amazon jungle where a tribe have been sacrificing people to The Great Ant God from Ataxia. Penfold is captured, and things look grim, but then Penfold's Aunt arrives from a taxi and tells them all to stop playing silly games.
Penfold puts on Danger Mouse's suit and can't get out. From then on everyone thinks he is Danger Mouse. Later, DM and Penfold go to Bratislavakia to find out why all the countries of Central Europe have swapped places. There they fall fowl of a mystical stone that causes people to swap bodies.
Crumhorn invents a chemical that allows him to create land sharks to terrorize London. Things get even more complicated when Penfold gets into the formula.
