With the only Regenerator destroyed, things are looking bad for Mars. The Biker Mice must take General Stoker (creator of the Regenerator) to Planet Earth where he can find the necessary tetra-hydrocarbons required to build another machine. But there is a surprise in store for the Biker Mice on their return to Chicago in the form of developer Ronaldo Rump, who has joined forces with the Catatonians to obtain a Regenerator (the ultimate land-development tool).