Chizuru Yukimura is on a quest to find her father, a physician named Koudou, who has been missing for months in Japan during 1864. In order to increase her odds of success, Chizuru disguises herself as a man and heads to Kyoto. Along the way, she observes a group of white-haired men brutally murdering a band of ronin which leads to her being captured by the Shinsengumi, a samurai group who intervene in the situation. The Shinsengumi are uncertain about how to handle Chizuru's presence, ultimately detaining her in their base to contemplate pardoning or executing her. Chizuru's luck takes a turn for the better when she discloses Koudou's name to the Shinsengumi, who have also been searching for him. Despite this, Chizuru learns of the connection between her father and the Shinsengumi and their allies, leading her to face a conflict between his past and the political issues of the present.