The protagonist is reincarnated in another world with cheat skills. However, in that world, humans and demons live together in peace. His dream of being popular in a harem in another world is shattered. One day, by chance, he enrolls in the private Monmusu Academy. The academy, under the name of coexistence between humans and demons in their adolescence, was established as a measure against the declining birth rate, where students learn about love and aim to reproduce beyond racial barriers. Even though the protagonist has cheat skills, he is a virgin with no assertiveness, and the Monmusu teachers decide to conduct naughty supplementary lessons for him.