Bumboo is a very strange car-like creature with a cute yellow body. He was born from a mysterious egg at an automobile factory. Having heard the first cries of a newborn baby, a boy named Ken comes to the factory and meets Bumboo. They soon become good friends and set out on their exciting journey. Traveling the world with his four-wheeled friend and Mister the dog, Ken faces big trouble from Doctor Monkey—who wants to get Bumboo into his own hands—but finds thrills and excitement around every corner.