In Edo-era Japan, Sanshiro diligently hones his sword-fighting technique at the kendo dojo, but no amount of practice can hide the fact that he is both clumsy and cowardly. When his samurai father falls prey to a gang of murderous phantom thieves while on night watch duties, Sanshiro is drawn to the banks of the Sanzu River that separates the worlds of the living and the dead. Here he encounters a strange being that introduces itself as a Shokera. The otherworldly apparition offers advice on how Sanshiro can avenge his father with the aid of a mysterious potion with the power to turn him invisible. But first Sanshiro must gather the ingredients, and his father’s killers might be closer to home than he thinks.