Koguma, a shy 2nd-year student in high school with no parents, no money, no friends, and no goals for the future decides one day to shop for a motorbike. When she buys an inexpensive used Honda Super Cub, it leads to events that will change her life.

When Koguma lets it slip in class that she owns a motorbike, she attracts the attention of Reiko, one of the girls who sits near her. Reiko insists on seeing Koguma's Cub, as well as showing off her own, and is pleased to meet a fellow Cub rider.

Koguma visits Reiko at her home, and the two have dinner together. Reiko recounts the story of how she took a job at the Mountain Hut Kikuya over the summer as a means to pursue her own dream, something which proved to be more difficult than expected.

The girls pack up and depart on a road trip to Kyushu, the most distant location their Cubs will take them, in order to shake off their winter doldrums and embrace spring. Along the way, Shii finds what she needs to help her continue her café project.