As a young boy, Murakami had a close friendship with a girl he nicknamed Kuroneko. Tragically, during an attempt to demonstrate the reality of extraterrestrial life to Murakami, she dies in an accident that he narrowly escapes. Burdened by guilt over his involvement, Murakami vows to spend his life proving the existence of aliens. Years later, a new student with enigmatic abilities joins his class, bearing a striking resemblance to Kuroneko and going by the name Kuroha, Neko.