The “Bobby” in the title is 17‑year‑old Akihiko Nomura, an underachieving high‑school student who lives for motorcycles. His grades are failing, and his father, a traditional, strict man who eventually gave in and let Akihiko have a bike, is doing everything he can to persuade him to apply to college. Akihiko’s mother is silent to the point of being almost absent, so his only support comes from his twinkle‑toed little sister, who is nosy but cheers him on in her own way. Akihiko spends all his time working on his motorcycle: cleaning it, tuning it, riding it. He is a true motorcycle otaku, and his latest triumph was having photos of himself on a road trip printed in a motorcyclist hobby magazine. The unexpected result of that feature is a girl his age, who bought that issue on a whim, writing him a long, dreamily romantic letter. Akihiko admits to his sister that he has never received a letter from a girl before. He replies with a simple “I got your letter. I'm happy 'cause it was from a girl.” Akihiko is not a well‑rounded kid; he barely speaks even to his own family, and his responses to the mystery girl are usually just a single sentence. His obsession with motorcycles consumes him to the point where he quits school to work at a biker bar. His father, unable to handle it, kicks him out of the house. Staying with a friend, Akihiko is delighted when his pen pal says she will call him. On that day, his boss at the bar takes him to a motocross track, but the day ends in a way no one would expect.