Isami Kondo is finally ready for the entrance ceremony of the National Defense Academy. Kondo, who is a regular high-ranking honor student in the national standardized mock exams, applied for this school because, "You can study for free, receive money, and put money into your family. It's three birds with one stone." Such Kondo's life at the National Defense Academy began. Tadashi Harada, Soji Okita, and Toraaki Takei in the same grade. Each of them has different goals, but a fun communal life with their friends should begin... The day after the entrance ceremony began mercilessly, it was a tough day beyond imagination. 4th grader Sakaki, the head of the room, and Nishiwaki, the sub-head of the room, fly! ! This is Defense University! !

Kondo and the others run around the National Defense Academy in order to manage their daily schedule. Numerous instructions given by seniors unwillingly. If the salute is weak, "20 reflection sentences!" If there is a mistake in the cleaning, "20 reflection letters!" What is this?! No time to study! In such a situation, Kondo finally moved. Kondo asks Sakaki about this situation, which can only be considered unreasonable. As expected, the answer returned from Sakaki, the demon senior...

Permission to go out for the first time since entering school. A defense college student who gets attention from girls when she walks around town in uniform. Kondo, Harada, and Takei enjoyed Yokohama Chinatown with sub-room chief Nishiwaki. Meanwhile, Takei wishes to meet her parents, and decides to act separately. When Kondo and the others return from their trip, Takei is nowhere to be seen! ! Again, collective responsibility for fear? ! And hell week begins. What is the ending that awaits Takei?! !

Little by little, Kondo and the others are getting used to the harsh daily life of the National Defense Academy. Such they will have a gun loan ceremony. However, in a gun dismantling class, Harada loses gun parts. Then Harada who repeats mistakes and spins around. Calls from his seniors are also frequent. Kondo, Okita, and Takei try to encourage Harada, but the worst is about to happen...

When Kondo wakes up in the middle of the night, Harada is nowhere to be seen! Did Harada escape from the National Defense Academy? ! Does that mean that you have escaped the fence? ! Kondo desperately searches for Harada, who has disappeared, and discovers Harada sitting alone in his thoughts. Kondo desperately persuades Harada. Meanwhile, Sakaki, a demon senior, comes... What is Harada's answer? ! And what is their future when something begins to change little by little in the harsh days of the National Defense Academy!? ?