In the Sengoku period of Japan, a young orphan named Kotarou and his dog Tobimaru steal from unsuspecting villagers in order to make ends meet. However, Kotarou is forced to remain on the run when he finds himself being hunted down by assassins sent by China's Ming Dynasty for mysterious reasons not involving his petty crimes. Fortunately, the duo run into Nanashi, a ronin who has taken refuge in a small temple, when Kotarou is attacked and Tobimaru poisoned. Although the samurai saves the helpless pair from their pursuers, he feels that there is no need to help them further; but when offered a gem in exchange for his services as a bodyguard, he reluctantly accepts Kotarou's offer of employment—just until Tobimaru is healed and the two reach their destination. As the three set out on a perilous journey, it soon becomes evident that their path is riddled with danger, as the Ming Dynasty has now sent a terrifying swordsman after them to capture Kotarou and fulfill a certain prophecy. In the Sengoku period, a rounin called Nanashi (meaning nameless) saves a young boy Kotarou and his dog Tobimaru at an abandoned temple. Kotarou has no family, is pursued by a mysterious militia organization from China and hires Nanashi as his bodyguard. Among the pursuers is a man called Rarou, a very skilled warrior with blond hair and blue eyes. He obeys an old man called Byakuran and is a member of the Chinese militia. Unlike his companions in the militia, he is not serving any Emperor and just wants to fight with the strong.