Bumboo is a sentient, car-like entity with a distinctive yellow body. He originates from a mysterious egg discovered at an automobile factory, hatching as a newborn. His initial cries drew a young boy named Ken, sparking their first encounter and forging a close friendship. This meeting launched their joint expedition across diverse locations to locate Bumboo's mother.

Bumboo exhibits a friendly and adventurous personality, frequently engaging in races against other sentient vehicles encountered during his travels. Exposure to flowers, particularly amapolas, grants him temporary surges of strength and speed, ensuring consistent victories in these competitions. Throughout the journey, he demonstrates a readiness to assist individuals facing difficulties.

The character faces persistent pursuit from a figure called Professor Honky-Tonk or Doctor Monkey, who seeks to capture him for undisclosed motives. This antagonism creates recurring challenges during Bumboo's travels with Ken and their canine companion, Mister. The expedition involves multiple encounters with similar talking vehicles, though Bumboo's specific connection to them remains undefined.

Bumboo's primary narrative arc concludes with the successful location of his mother after extensive searching.