The Biker Mice from Mars are three Freedom Fighters from Mars who just happen to look like giant Mice! Escaping their war-torn planet of Mars, the three crash-land in Chicago, in the Wriggly Stadium Scoreboard.

While exploring the city, Throttle --the gold-tan leader-- develops bike problems, and the three search out a garage so that Vinnie --the white-furred hot-shot-- can make repairs. They find a garage called, "Last Chance Garage", and when Vinnie goes to investigate, he finds the owner --a pretty Earth woman named Charley Davidson-- being harrassed by Greasepit, a huge, oil-oozing mountain of a thug. Vinnie attempts to defend Charley, only to land on the floor, against the wall.

When Greasepit utters the line, "What are youse; a man or a mouse?", Throttle and Modo --the huge gray-furred Mouse-- crash through the window. They take off their helmets, revealing their mousy features, and Modo answers "Mouse." To which Throttle adds, "You got a problem with that?"

What ensues is a short, but fun, brawl, ending in Greasepit being covered in tires and rolled off out of the garage. The Mice then turn to check on Charley. Charley is holding a large wrench, and seems to be about to "brain" Throttle with it before he calms her down and reasures her that they won't harm her. Throttle uses "Touch-Telepathy" --by putting his attennae to her head and showing her images in her mind-- to explain who they are, where they are from, and why they are on Earth.

Charley proves to be a super-mechanic, as she is not only able to fix Throttle's bike, but she adds weapons to each of the bikes (something she does throughout the series, as well.).

After a second confrontation with Greasepit, the Mice go off to Limburger Towers, to confront Lawrence Limburger personally. Limburger, it seems, has been buying up the town and digging it up, but never building on the land.

The Mice run a gauntlet of Limburger's goons, and finally manage to end up in the office of the tower. There, they find out the truth about Limburger --he's a Plutarkian! Plutarkians are the race of fish people from the planet of Plutark, who has taken over and strip-mined Mars. Now, they plan to do the same to Earth.

The Mice meet up --again, it seems-- with Dr. Karbunkle, a mad scientist type with a skinny body and a shock of orange hair. Karbunkle is the one that replaced Modo's arm with the bionic one, and Throttle's eyes with the malfunctioning cybernetic eyes. Karbunkle is also able to call on villians from many different dimentions, and he has now called on the X-Termenator --a robot that looks and sounds like Arnold Swarzanager.

After a chase through the city, Throttle manages to trick the robot into a nuclar waste building. After the robot falls into the oozing waste --and intoning the classic, "I'll be back!"-- Throttle rejoins the others at the ball field, where their ship falls completly into the scoreboard. Charley suggests that the Mice use the scoreboard for a hideout. Limburger and his goons would never to think to look for them there. The Mice agree. Then the group rides off for some hot dogs and root beer.