Ruby's dream: to become a famous treasure hunter. Jio's dream: to rule the world!

In a not too distant future, mankind battles over O-Parts, powerful relics from an ancient civilization. Jio is a young boy with a tragic past who only trusts one thing in the world: money. Little does he suspect that he is also a very powerful O-Parts Tactician (O.P.T.), and inside him sleeps a demon of incredible ferocity. With his partner, Ruby, Jio embarks on a dangerous quest to acquire as many O-Parts as he can.

To defeat the legendary O-Part Mexis, Jio was forced to make a dangerous pact with the evil spirit that dwells deep within his heart. Now that the time has come to resume his battle with the man responsible for shattering his old O-Part--Wise Yury, the Crimson Magician--will Jio's newfound strength aid him in stopping this powerful O.P.T., or will his eternal soul be lost in the process?