The narrative unfolds during a clash between the Krakozhia Dukedom and the Grania Republic. Amidst the hostilities, a hero emerges in the form of Souhei Yano, a high school student. Suddenly, two female soldiers, First Lieutenant Ruto and Second Lieutenant Haruka, arrive at his home in tanks, interrupting his daily routine. To make matters worse, an enemy soldier named Shachirofu also appears, brandishing firearms without hesitation.