After an incident, interactions with many different worlds started in the modern society. Elves, women knights, vampires, cat eared girls, fairies, and even demon lords are freely walking in Japan, and to allow them to study the special class "Itoku" was created! In Itoku, a boy, Yakuma Mamoru, became the class representative and began a fullfilling school life as his classmates from different worlds relied on and became attached to him!