The young teacher, Shin Asada, is convinced by Shizue Nijou, the head of his new school, that he must have sex with her and Eri to prevent a demonic attack. When a magical fog then rises that will bring death to many of the high school girls most affected if he doesn’t have sex with them, he becomes the seed of hope. This sounds very familiar to Kirika Jinguuji, and Rio Teikei knows more about the phenomenon than Shin has been told so far. So he tries to fulfil the mission assigned to him without overthinking about it, which may not be the best of decisions...