In early 17th-century Japan, the peace under the Tokugawa Shogunate has led to a period of stagnation for the Iga and Kouga ninja clans, whose members possess extraordinary abilities. Historically enemies, the clans have been forbidden from waging war against each other under a peace treaty. However, the fragile peace is upended when the Shogun, seeking to consolidate his power and eliminate any threats, deviously hatches a plan. He issues a directive that pits the two clans against each other in a contest to the death. Five of the best ninjas from each clan are to fight in a battle that will ultimately determine the successor to the Shogunate. The story focuses on Gennosuke from Kouga and Oboro from Iga, who are in love with each other but are leaders of their respective clans. Their love is challenged by the imposed conflict that demands their allegiance to their clans and the cruel fate that they must face as participants in the battle.

Forced into the ensuing battle, both Gennosuke and Oboro must navigate the treacherous realm of political intrigue and their profound love for each other, while leading their members in a fight for survival. Surrounded by betrayal, they must confront not only the skilled warriors from the opposing clan but also the question of what they value most: their loyalty to their clans or their love for each other. The merciless decree of the Shogun sets the stage for a tragic tale of love, honor, and sacrifice.