A peace treaty has been in effect for hundreds of years to prevent a war between Earth and the Black World. Although it's set to be renewed, evil forces want to make sure that doesn't happen. To ensure it does, hard-bitten human Taki Renzaburo and sexy demon Makie are charged with protecting a diplomat, Mayart , who holds the key to peace. But, with an army of multidimensional assassins on their trail, it won't be easy.