Kiyomi Hoshita is a peerless warrior from Kyotasa, the land of the greatest swordmasters but she also happens to be a mere seventeen-year-old girl. When she is called upon to use her skills to fight for her clan in order to seize a throne that does not rightfully belong to them, she makes the painful choice to flee her homeland, leaving behind everything she knows and loves rather than allowing herself to become a murderer of her own countrymen. Having exiled herself from her own country, Kiyomi searches the lands beyond for a cause worthy of her blade, but she finds that the outside world is harsher than she had imagined. The entire civilized realm is in a state of war against an invading barbarian horde. Confronted by the suffering of those struggling against the invasion, Kiyomi must make a decision: Will she lend her abilities to these foreigners and join this war after having fled her homeland to avoid another? And if so, can she and her allies uncover the identity of the shadow organization that orchestrated the invasion in time to stop them?