The protagonist, Yukimura Chizuru, is the daughter of a doctor who works in Edo. The father leaves Edo to work as a volunteer doctor and moves to Kyoto without his daughter. As time passes by, Chizuru starts worrying about losing contact with her father, so she decides to go to Kyoto in search of him. On the way, Chizuru is attacked by few ronin and witnesses a fight between an oni and the Shinsengumi. After saving her and taking her into custody, the Shinsengumi debate on what to do with Chizuru when they discover that she is the daughter of the doctor they are also looking for. In the end they decide to become Chizuru's protectors and help her look for the missing father. She is to live with them as they discover mysterious secrets and fights against the Bakumatsu.