In a near-future Japan that has become a dependent state of a foreign power after a world war, lives a girl named Masamune. To fulfill her clan's mission of protecting Mimikado, she participates in peace talks between the new political party "Mitsurugi"—composed of samurai and aiming for dominance by force—and the Japanese government. However, the talks collapse due to the schemes of Mitsurugi's leader, "Iwakura," and Mimikado is framed, becoming a target for assassination. To protect Mimikado, Masamune takes him away from the meeting venue and decides to embark on a journey to her hometown, "Akizuki Village," to escape Iwakura's pursuit—