Σ1, Ε1: A young woman called Yukimura Chizuru travels from Edo to the capital, Kyoto, in search of her missing father. Once there, she's nearly attacked by a monster who is thirsting for blood. The monster, a rasetsu, is slain by group of men feared as assassins, the top officers of the Shinsengumi—Hijikata Toshizou, Okita Souji, and Saitou Hajime. Chizuru stays with the Shinsengumi to search for her father, Koudou. Then, one day, they receive testimony that someone has seen her father near a certain shop. When Chizuru arrives, she gets caught up in a scuffle...