As a child, Aoi Yukimura adored mountains and was passionate about climbing. However, a playground accident has since left her afraid of heights, turning her toward indoor hobbies. Unfortunately, now a shy and timid first-year high school student, Aoi has become so absorbed in these pastimes that she can barely socialize with others, leaving her practically friendless. It is only when she runs into the lively Hinata Kuraue, an old friend from her climbing days, that things start to change.