In the prosperous and picturesque Great Japan, a looming danger threatens the nation. Master Samurai, enigmatic guardians, stand as the last line of defense. When young samurai Muneakira Yagyuu is summoned to Buou Academic School by the student council, he enters a world where warrior offspring are groomed for leadership under the Tokugawa Shogunate's rule. Guided by President Yoshihiko Tokugawa and his sister Sen, Muneakira faces a turbulent welcome. Amidst chaos, a radiant light fills the sky, heralding the arrival of Juubei Yagyuu, a mysterious girl who shares a startling connection with Muneakira. Through an unexpected kiss, Juubei unleashes a hidden power, binding their fates together. As questions swirl about Juubei's origin and the enigmatic Master Samurai, Muneakira is thrust into a battle that threatens Great Japan's very foundation. To safeguard his homeland, he must unravel the mysteries behind the legendary warriors and the transformative kiss that awakened Juubei's dormant abilities.