In a suburban San Fernando Valley tomato garden in Los Angeles, Theo, self-named "Turbo", is a garden snail who dreams of being the greatest racer in the world, just like his hero, five-time Indy 500 champion Guy Gagné. His obsession with speed often makes him an outcast in the slow and cautious snail community, and a constant embarrassment to his older brother, Chet. One night, Theo wanders onto a freeway to admire the traffic and wishes upon a star, later revealed to be an airplane, that he was fast. Suddenly, he is sucked into the supercharger of a Chevrolet Camaro drag racer, fusing his DNA with nitrous oxide. When he wakes up, he possesses superspeed and some characteristics of a real car. He finds this may be the thing he needs to achieve his life-long dream.