Since the time of ancient Japan, Sumeragi clan has been the leading group of Onmyoujis who guard the souls and spirits. This is a story which concentrate on the social background and the inner feelings of the young leader of Sumeragi clan -- Subaru Sumeragi, his twin sister Hokuto Sumeragi, and their friend -- a generous vet as well as a ying-yang magician called Seishirou Sakurazuka who seems to be hiding his darker side of his character. The three of them help get rid of the darkness in the demonic city of Tokyo.