Nakano Akane, a genius student at Seiran Gakuen, excels academically but feels bored and directionless, unable to find meaning in life.

Summer 1978. High schooler Kurita is inspired by Star Wars, and films a spaceship scene on a 8mm camera together with his friend Ozawa. When the class is discussing a project for their school festival, Kurita's suggestion to make an SF movie ends up winning. Together with their movie fan classmate Sasaki, the boys start to plan a movie and manage to convince Yamashita, the prettiest girl in class, to star as the heroine. Over the summer vacation, the four shoot their movie, "Time Reverse", where an alien spaceship arrives on Earth to turn back time in order to save mankind from itself.

YouTuber Tomoki Uchikawa, along with his friends Hinako, Souta, and Nanae, head to the former Ishio Village, where there are rumors of people being spirited away, to film a video investigating urban legends. However, their whereabouts remain unknown, and the police discover the rental car they had rented near a tunnel on the outskirts of the village. The video cameras left behind there show shocking images of locked houses, children in armed uniforms, imprisoned adults, and adults being infected by a strange disease, a rotten demon, that occurs on the night of a new moon.