There's Earth, which we're all familiar with, and then there's the Black World, a parallel reality that few people are aware of. A contract between the two worlds has been observed for generations to ensure peace, and terms must be negotiated and renewed soon to maintain relative harmony.This time, however, there is a militant faction that will stop at nothing to block the signing of a new inter-dimensional peace treaty. Two operatives from the Black Guards, an elite group dedicated to maintaining the balance between the two worlds, are tasked with ensuring the treaty's success.