 There is Earth, our familiar world, and then there is the Black World, a parallel dimension that very few people are aware of. For centuries, a pact between the two worlds has been observed to maintain peace, and terms must be negotiated and renewed soon to continue relative harmony. This time around, there is a militant faction called The Radicals that will stop at nothing to prevent the signing of a new treaty for inter-dimensional peace. Two agents of the elite organization known as the Black Guards - defenders of the balance between the two worlds - are charged with insuring the success of the treaty. Taki Renzaburo is a (Human) black guard agent from shibuya and Makie a black guard agent who is a from the black world and there mission is to protected a man named Giuseppi Mayart, a 200 year-old man. Mayart is the only man who can keep the peace between both worlds, but if the The Radicals kill Giuseppi Mayart the peace between the human world and the Black World will end in terror. Can Taki & Makie protected for long?