Year 4, Kouwa era. After "The Day of Miracles," large-scale conflicts between nations ceased, and the world enjoyed a period of peace. However, conflict was not entirely eradicated. Seeds of conflict inevitably sprouted, sown by those who could not survive without conflict, those who sought wealth through conflict, and those who simply desired conflict. An organization existed to nip these seeds of conflict in the bud and prevent conflicts from escalating. Its name is "Izayoi," a secret agency established by Sumeragi Kaguya, who once served as chairman of the United Federation of Nations. Hakuba Sōga, a member of Izayoi, as Agent Shinigetsu, along with his assistant Satori, is tasked with pursuing the mysterious black Nightmare Frame, Pure Elements G.