When Hachi goes home to visit his mother for his birthday, Joker comes along, looking for treasures in his ninja mansion. They`re met in the ninja village by Hachi`s precocious sister Kurumi and hole-digging brother Ichimaru. The sight of Hachi`s family causes Joker to remember his own. When Joker removes the lid from a jar Ichimaru digs up, it unleashes a ninja called Yasha-oh, who was sealed there by Hachi`s ancestor long ago.