In a world where humans, demons and angels all live in harmony after countless battles, Shiraki Ryu, an 18 years old Japanese girl that just graduated from high school was now standing in front of an important decision. Shiraki has to choose between going to university or helping her grandpa with his shop, with the possibility of taking it over, but everything changed when the events of that fateful night occurred: after learning the truth about her parents and the laws that binds her future, her grandpa was kidnapped by an organization called Stigma, an organization that plans to destroy the peace of all the worlds. Shiraki will find herself studying in the Demon World in order to become stronger with the objective of destroying Stigma, saving her family and unveil the true past of her parents.