For years Pokerus has been around yet little is known about this virus. It seems to have no known effect on Humans, and on Pokemon it is only known to boost Pokemon's attributes. However, in the region of Johto, Pokemon have started become very sick, this strange illness has started to spread so rapidly around the region, that nobody is allowed to enter or leave the region to stop the spread to other regions. Yet, some Pokemon in the Kanto region has started to show signs of this illness. It is thought that perhaps Pokerus may actually be the cause, however as it's wild Pokemon that are generally found sick, and Pokerus's known effects wear off after a period of time, it can not be conclusive that Pokerus is actually the cause. A group of trainers will be embarking on their Pokemon journey's in Kanto, and will encounter said sick Pokemon. It will take their efforts combined to figure out what the cause is, if Pokerus is involved in anyway shape or form.