Hunted by the Mings from China, young Kotaro and his dog meet Nanashi, a samurai who is constantly being haunted by dreams of the past which lead him to seal his sword. Among the Mings is a fiercesome Western fighter named Rarou, who desires only to find a worthy opponent.

When both groups clash with a Sengoku-era feudal lord, a proud general, and monks torn between faith and survival, the reason behind the Mings' pursuit tests the bond between Kotaro and Nanashi.

Based on the anime film of the same name.