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.