Demon Virus: 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.