Jiro Azuma is descended from of a long line of shinobi, and he also can talk to animals. One day, he rescues a very unique black cat named Rago, a supernatural being, and is dragged into a secret supernatural war.

In order to save Jiro's life, Rago pledges loyalty to Amagi, his mortal enemy! But Rago has no intention of letting his power be used by evil forces, and so when he joins Amagi, he leaves all his power behind in Jiro. Outraged at the unexpected betrayal, Amagi unleashes his wrath upon Rago!