Pokemon Cure and poison is set in an alternate universe where pokemon fusion is common and legal. It was only tested on the first generation of pokemon so the other 6 are roaming around as normal. Kiryu(Male protagonist and his sister Kee (Female protagonist), along with a few other friends travel the region to study, capture and train fusion'mons and normal pokemon while trying to stop the plans of Black Thunder an evil organization who try to reset the universe by using the powers of a forgotten legendary pokemon, Darlish.