Ryu, is a modern super ninja and the best friend of Katsumi's lost brother (Hayate-also known as "Ein"). Being a super ninja, Ryu, has the responsibility to confront "Bankotsuboo," The Evil Tengu who came from the dark world into human existance. To face the Evil Tengu would be a suicidal act for any human being, but Ryu owes it to mankind to confront his fate....