Cholera takes the mother of Shotaro Yukimura, fourteen, and his younger brother Gentaro, ten, in the unravelling last years of the Tokugawa shogunate. Her final words send them after the sword their samurai father left behind and the strength to outlast an age in which the weak simply die. With nothing else to their name, the brothers go looking for someone to teach them the blade, and set out on what they call Sidooh, the path of the warrior.