The anime is a prequel story set before the events of the manga. It’s tells the story of Kagura Tsuchimiya and Yomi Isayama, swordswoman and heirs from a long line of Japanese exorcist families. Both girls suffered a personal tragedy in their lives yet grew close together like sisters. As both of them grow up, they both must overcome their weaknesses, accepting being the daughters of exorcists and following their families tradition. Yet tragedy will befall both of them which will spiral these two ‘sisters’ into bitter enemies.