While wandering through the wilds of Japan with his 3-year-old son, Daigoro, (Akihiro Tomikawa), assassin-for-hire Ogami Itto (Tomisaburô Wakayama) finds his next assignment -- he's hired to kill a merchant intent on revealing corporate secrets. On Ogami's tail, however, is a trio of female ninjas who have been sent to kill him and his son. When Ogami is wounded in battle, the toddler rises to the occasion and helps nurse his father back to health in time for a second sword fight.