At the end of the 20th century, 15-year-old boy Sakakibara Tsuneichi (voiced by Abe Atsushi) came to his deceased mother's hometown, Yamiyama City, because his father went on a business trip overseas. He temporarily lived in his aunt Mikami Reiko (voiced by Misada Miyamaki)'s house and waited for transfer to a new school. During this period, his old illness relapsed and he was hospitalized. One night, Tsuneichi encountered a beautiful girl wearing a sailor suit and an eye patch on her left eye in an empty corridor, which seemed to foreshadow the beginning of an extraordinary life. After being discharged from the hospital, Tsuneichi successfully transferred to Class 3, Grade 3 of Yamiyama North Junior High School. The classmates were warm and friendly, but they seemed to be hiding some secrets from him, and he also saw the eye patch girl in the hospital again - his classmate Mizaki Naru (voiced by Takamori Nazumi). When he tried to approach Mizaki, he didn't know that he had accidentally opened the gate of death... This film is adapted from the original work of the famous orthodox mystery novelist Yukito Ayatsuji and the original work that was comicized by Hiro Kiyora.