There is a small town somewhere in Japan, which is surrounded by nature. In this town, there is a large awe-inspiring school, Otobashi Gakuen; which was founded to make the students familiar with nature.

Kurusugawa Himeko is a normal student who goes to Otobashi Gakuen. She leads bright and enjoyable school days with her two friends, Himemiya Chikane and Oogami Souma.

Chikane is the only daughter of a distinguished family, and excels at both academics and sports. She is also kind and beautiful, making her very popular among the other students. Souma is Himeko's childhood friend. He has problems expressing his emotions directly, but he is very sincere.

On Himeko's 16th birthday, a dark moon blocks out the sun, and the Orochi come forth to destroy the world. But why are they targeting Himeko?

[Source: AniDB]