Koguma, a high school girl in Yamanashi, leads a quiet but empty life: she has no parents, friends, or hobbies. One day, Koguma gets a used Honda Super Cub motorcycle, and experiences motorcycle riding for the first time. Running out of gas and hitting detours become a small source of adventure in Koguma's life. She is satisfied with this strange transformation, then her classmate Reiko starts to talk to her, as she also goes to school by motorcycle. One Super Cub begins to open up a lonely girl's world, introducing her to a new everyday life and friendship.