The birth of these saviors are called... well, Miracles. These saviors, A.K.A. Crossovers, are people born during an MD Wave. The MD Wave is a plague that divides our society into different parts of dimensions, such as Heaven and Hell, Past and Future, and other oxymorons such as these. In other words, when the Heaven and Hell MD Wave hits, our whole society will be equally divided into Heaven and Hell. The Crossovers are sent to Partica Island for a briefing of their life mission...
A mysterious God-like figure named Celestial tells the 5 Crossovers that these MD Waves are actually creatures called Viruses, that resemble the type of virus found on computers; except they are alive. Though there are only 5 MD Waves, there are billions more Viruses, ready to Plague the Universe once more. The Crossovers are here to put a stop to all of it...