In a world where people coexist with Juujin (literally: "Beasts"), genetically mutated animals, which have surprisingly similar features, with the exception of the limbs, such as tails and ears, Juujin are often found as workers in labor or pets. This is until a new type of Juujin: Evolution, EVO for brevity appears. These Juujin have special magical abilities that they use against the human race. Peka, one of these Evo, grew up with his teacher Yamato Yamamoto. Yamato's mother works at the Health Center, the only agency with jurisdiction over Juujin, and developed a special collar who can seal the authority EVO. Nadiv is a necklace, so as not to give your own pitch to go crazy,