The narrative unfolds amid a conflict between the Krakozhia Dukedom and the Grania Republic. Amidst the hostilities, a savior emerges for the Krakozhia Dukedom: a high school student named Yano Souhei. Two female soldiers, First Lieutenant Ruto and Second Lieutenant Haruka, arrive in tanks to disrupt Souhei's daily routine, accompanied by the enemy soldier Shachirofu; all of them wield firearms without hesitation at his residence.