Vinnie, Modo and Throttle are three Cave Mice from the planet Mars. Their planet was occupied by the Plutarkians, a race of foul smelling evil fish men, who annihilated the Cave Mice population (apart from our heros). The Plutarkians wanted the land and bought up everything on the planet and strip mine it back to their own planet. Our heroes were the 3 leaders of the Mars rebellion.

Afterward the Mice travelled the Cosmos racing their bikes until their ship (a Cycladrone-Thunderbike) was attacked by a Plutarkian Destroyer, where they crash landed on planet Earth, in Chicago. To be precise, their ship crashed into a baseball scoreboard during a game, where the Biker Mice ejected their bikes before impact - nice entrance!

But one of their bikes was damaged and they had to find a garage and they found the Last Chance Garage in Shy Town. Inside Charlie was being threatened by Grease Pit, a large oaf who oozes oil. His boss Laurence Limburger wants the land the Garage is built on.

The Mice stepped in and helped Charley. She fixed the bike and added a few extras. They then found out that Lawrence Limburger is infact a Pluarkian in disguise and he was under orders from the Plutarkian High Chairman - Lord Camembert (Supreme Leader) to strip the earth of its natural resources just like Mars (again by buying up everything).

Dr Karbunkle is one of Limburger's henchmen and invents things to help get rid of the mice. Modo especially dislikes Karbunkle, as it was him who experimented on the mice and removed Modo's arm  in his Laboratory on Mars (later he had another one built to replace it). Luckily the mice escaped from his Laboratory, much to the displeasure of Limburger.

They still live in the ship hidden in the scoreboard and use it as a base to fight the evil Plutarians here on Earth.