Charley Davidson is the mechanic and owner of the Last Chance Garage in Chicago. She led pretty much a normal life until she met the Biker Mice from Mars.
A hard-working, honest, compassionate young woman, Charley is nevertheless a tough-minded person. So when Greasepit, the massive, oil-dripping henchman of Lawrence Limburger, demanded that she sign over her garage to Limburger, it was a natural reaction for her to tell him to "Get lost!"
Unfortuantly, Greasepit was not the type to back off. He keep harassing her, threatening her, to sell the garage to Mr. Limburger. To put it in his words (quote) "What Lawrence Limburger wants, Lawrence Limburger GETS!" (unquote)
It's when Cherley slips on the floor and Greasepit thinks he has her, when Vinnie makes his "grand entrance". (Well, that's what Vinnie probibly thinks it was, anyway...)
After some macho postering from Vinnie, after which he lands on the floor, his legs against the wall of the garage after attempting to sock Greasepit while swinging from a rope (hey, it looked cool until Vinnie slipped in a pool of oil and landed in said position...). It was then that Greasepit uttered those immortal words:
"What are youse: A man or a mouse?"
As if in reply, Throttle and Modo crashed through the window. They remove their helmets.
Throttle: "You got a problem with that?"
Then, the overly-oiled thug makes the mistake of calling the Mice "rats".
Modo: "RAT!? (his good eye blazes red). My momma didn't raise no STINKIN' RAT!" (You can actually see a frightened Greasepit reflected in the glowing eye.)
After dealing with Greasepit, the Biker Mice quickly befriend Charley.
Since then, Charley Davidson has been the Biker Mice from Mars' closest friend and ally on Earth. She is very intelligent, as she is not only able to repair alien technology (the Martian bikes), but can also modify it, improving it beyond its orginal limits of output.
Of course, hanging around the Biker Mice from Mars, Charley's had to learn a few things. Which is where the Marksmanship, Tracking, and Unarmed Combat abilities come from.
Charley is armed only with the tools of her trade --screwdrivers, wrenches, etc.-- but is sometimes also armed with a Martian blaster. It is unknown if this is a borrowed weapon for the episode, or if the Mice have given it to her as a permenant weapon.
Charley also drives a tow-truck and sometimes rides a blue, Terrian bike. If not driving the truck or riding her bike, she is seen riding behind Vinnie, whom she seems to have formed a romantic bond with.