Akashi Eito has failed miserably on all high school admissions exams but somehow, he receives a letter of acceptance from a school he does not remember applying for. He nevertheless happily enrolls, expecting to live the ideal school life, but his aspiration are quickly destroyed as he discovers that this mysterious school is a training institution for secret agents!

Immediately, Eito wants to return home and live a normal life with his normal family, until the director of the school makes a shocking revelation: Eito's deceased father was also a secret agent! He subsequently wants to know more about the past and memories of his father, so he decides to stay in this school. However, as a student of this institution, Eito will have to face a deadly exam made to test the skills of all new students...