After spending lethargic days without parents, friends, or hobbies, Koguma bought a Super Cub, and several months have passed. As the seasons change, the wind blowing at the foot of the Minami Alps grows colder day by day. Delicate fingers, an engine that doesn’t start easily, and the biting wind that freezes even the lungs. Snow-covered roads—Koguma faces the trials of the season alongside Reiko, who also rides a bike. As Koguma begins to change little by little after encountering curves, her classmates Eni and Shii show interest in her... Thus begins the girls' challenging yet enjoyable winter with their bikes.