The "Bobby" in the title is actually seventeen-year-old Akihiko Nomura, an underachieving high school student with a deep passion for motorcycles. His grades are poor, and his traditional, strict father—who seemingly relented at some point to let him own a motorcycle—is trying every method he can to push the boy toward college. His mother is so quiet she might as well be invisible. His real support comes from his lively little sister, who is nosy but encourages him in her own way.
Bobby hardly does anything except work on his bike. He cleans it, tunes it, and rides it. He could be called a motorcycle otaku. His latest achievement seems to be getting photos of himself on a road trip published in a motorcyclist hobby magazine. This leads to an unexpected outcome: a girl his age, who picked up that issue on a whim, decides to write him a letter—a long, rambling one, but dreamily romantic. Bobby admits to his sister that he has never received a letter from a girl before. He writes back: "I got your letter. I'm happy 'cause it was from a girl."
Bobby is not a well-rounded kid. He barely speaks, even to his own family, and his replies to the mystery girl usually consist of a single sentence or so. His motorcycle obsession consumes him to the point where he happily drops out of school to work at a biker bar. Naturally, his father, at a loss, kicks him out of the house. Staying with a friend, he is thrilled when his female pen pal says she will call him. On that day, his boss at the bar decides to take him to a motocross track. But that day will not end in a way anyone expects.
