During the war, a group of warriors known as the Ninku fought against the Imperial Army and nearly annihilated it. However, in the end, the Ninku were defeated and scattered. Following the war, the Imperial Army established itself as the protector of the people through propaganda. They also succeeded in convincing the public that the Ninku were the villains who had started the conflict. Fusuke appears to be a child, but he is actually the former captain of the First Ninku Division. His mother was taken during the war, and after the Ninku's defeat, he embarks on a journey to find her. Along the way, he meets Aicho and Touji, both former Ninku captains, and together they fight against the Imperial Army, which attempts to eliminate the last remaining Ninku. The Ninku are a clan of extinct ninjas who command esoteric and powerful techniques; consequently, many other groups constantly try to steal these techniques to take over the country. Their primary target is Fusuke, a strangely looking kid who is one of the most powerful Ninku ninjas. Fusuke, along with other Ninku ninjas possessing different specialties, must fight the threats that caused the downfall of the Ninku clan.