Aoi Yukimura is invited by two of her classmates to have tea after the first day of high school. However Aoi frantically rejects their invitation due to her difficulty in interacting with her peers, preferring instead to further her hobbies. Aoi's childhood friend, Hinata Kuraue then approaches and invites her to climb mountains like they did in the past, much to her reluctance since she had developed a fear of heights. While remembering that hanging out with Hinata only brought her misfortune, Aoi is reluctantly dragged to Hinata's home after school to plan a mountaineering expedition.