Akashi Eito has failed miserably on all of his high school admission exams but somehow, he receives a letter of acceptance from a school he does not remember applying to. 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 institute for secret agents.

Immediately, Eito wants to return home, 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 remain at this school. However, as a student of this institution, Eito will have to face a deadly exam specifically made to test the skills of all new students.

Follow this story of action and espionage, in which our hero, who lacks physical strength, compensates for it with great bravery, and captivates everyone around him with the power of his courage and friendship.