Aiba Hashiru is a hero who was summoned to another world. After defeating the Demon King, he returned to his original world due to some troubles, and returns to his former life as a new teacher with his abilities as a Hero warrior. However, among his students, there are those who fight against monsters, aliens, and a mysterious criminal organization. This is a story about the life of a former hero, who doesn’t particularly hide or hold back his heroic abilities