In a parallel realm called Magano, infested with monstrous entities known as 'Kegare,' exorcists combat these impurities. Benio Adashino, a gifted exorcist acknowledged for her prowess, is beckoned to Tokyo by the Exorcist Union. During her journey, she collides into Rokuro Enmadou, a young exorcist with a turbulent history. Amidst the relentless threats of Magano, a Kegare abduction of children prompts Benio to leap into action, pulling Rokuro into the chaos. Struggling in a dire confrontation, Benio finds unexpected aid from Rokuro, unveiling his potential as her rival in skill. 'Sousei no Onmyouji' narrates the tale of these two exceptional exorcists destined to be the 'Twin Star Exorcists,' foretold as the parents of the Miko—the rebirth of Abe no Seimei—who will purify the world of all impurities.