Shizuku Ota

The Fourth Industrial Revolution has led to the development of cutting-edge technologies that have rapidly evolved the world. As a result, schools have begun incorporating these technologies into their curriculum, leaving behind the ways of the old. One such institution is the elite Yuyu Girls' Vocational High School, where both Serufu Yua and her childhood friend, Miku "Purin" Suride, have applied. Although the tech-savvy Purin is accepted to Yuyu High, the accident-prone Serufu is rejected and enters the traditional Gatagata Girls' High School instead, driving a wedge into their friendship.

Maki Maki, Sebuki Suzume, Beppu Tsukasa and Iemori Yutaka happen to meet and form a quartet. They even begin to live together in Karuizawa during the winter, but there is a big hidden secret.