Shinkuro Takanoha is the 17th head of the Takanoha clan, who are responsible for covert operations for the Tokugawa Shogunate. Amidst the chaos of the end of the Edo period, he is ordered to guard Kaishu Katsu. Meanwhile, his twin brother, from whom he was separated, has become Soji Okita and is in the Shinsengumi—their destinies intersect!