In 1840 in Satsuma (present-day Kagoshima Prefecture), Kokichi Saigo is having days of training and studying with friends in town. At the domain's biggest event held at a temple, he has a fateful encounter with Nariakira Shimazu, the son and heir of the Satsuma domain. However, Kokichi is slashed on the shoulder with a sword by a boy who bears a grudge against him, and becomes unable to swing a sword again.