In 1860's Edo, Japan, Chizuru Yukimura, a 16-year-old girl, leads a modest life under her father's care. When her father's absence and halted letters cause worry, Chizuru ventures to Kyoto in male guise to trace him. Amidst samurai threats and encounters with an otherworldly figure, a Shinsengumi warrior rescues her. However, her knowledge prompts her capture by this enigmatic group. The Shinsengumi, a covert faction, spares Chizuru upon realizing her connection to her missing father, whom they seek for their own motives. As Chizuru aids her new companions in the quest for her father, she unravels profound mysteries and forges deep bonds with these dashing warriors, altering all their fates irrevocably.