In World War II, Japan turned to Onmyoudou magic, led by the renowned onmyouji Yakou Tsuchimikado, to gain power. Regrettably, Yakou's actions caused the infamous "Great Spiritual Disaster," and Japan's downfall ensued. To prevent further calamities, the Onmyou Agency was created. Nowadays, Onmyoudou has evolved and proven its relevance in various fields. However, not everyone possesses the natural talent to employ it, including Harutora, a member of the Tsuchimikado family. Despite his responsibility to protect Natsume, the potential heir of the significant Tsuchimikado family and Yakou's supposed reincarnation, Harutora lacks the requisite knowledge and prefers a typical life. Nonetheless, when a top Onmyou Agency member plots to recreate the tragedy that devastated Japan, Harutora must overcome his reluctance and fight to defend Natsume.