Accidental Samurai Spy

Aritomo Genji, a twelve-year-old heir to a samurai lord, training to become a warrior, yearns to fight against his family's archenemy, the Kuroda clan. But he and his loyal dog Tama are sent away on a ship to keep them safe. After the ship sinks in a typhoon, and they're rescued by Kuroda soldiers, Aritomo must pretend to be an orphaned peasant.

As reward for saving the life of Lord Kuroda's daughter, Aritomo and Tama live in the enemy's castle where they become friends with the girl. When Aritomo learns of a plot to massacre his clan, he must choose between saving his family and staying true to his friend.