After studying abroad​ in order to learn fencing, Utsugi Hinata returns to his home country Japan for the first time in several years, and is greeted at the airport by a woman named Nina Clione, Ginran Academy's principal and chairwoman.
Guided by Nina, Hinata is led to the school and becomes fascinated by the scene that is being unfolded there. Sparkling sword fight​s and girls covered in beautiful armors.
"This is "Butoh: Cadenza", a match between the knights."
"At this school, we teach "Chivalry​". Hinata-kun, would you like to teach fencing here?"
To evaluate his skilled in fencing for Nina, Hinata decides to experience "Butoh" immediately. However, instead of a gorgeous armor he thought he would be wearing, what is prepared for him are a sightly lewd bodysuit and even a wig, Hinata is made to dress up like a girl.
It is only possible at the "Theater" of Ginran Academy for the 3D armor and sword in hand to be projected virtually using magical technology.
There, he confronts a knight who is considered to be the strongest in the school, and wins.
"That girl, who on earth is she?"
"This girl is a transfer student who will be assigned as an assistant instructor starting tomorrow, a second-year student in the Knight Training Department, Unohana Hina-chan!"
Thus, Hinata, or Hina, in a place where the maidens gather, begins to live a double life​ as an instructor and a student while being dressed as a girl.