Miyoshi Haruto, who became a Marine at the age of 9, has finally gained some measure of freedom after completing numerous missions for the U.S. government. However, shortly after returning to Japan, he is enrolled in ANHS by the renowned diplomat Matsushita Takehito with the condition of protecting his daughter, Chiaki, while blending in and living the life of a normal high school student. Once inside ANHS, Haruto encounters Ayanokouji Kiyotaka who piques his interest, someone around who he must remain vigilant and close at the same time. As he navigates this new environment, he discovers a variety of people and faces the challenges of the school. Will he join forces with Kiyotaka to reach class A or be against him? All the COTE characters belong to Shogo Kinugasa.