The Kouga Manjidani and the Iga Tsubagakure ninja clans have been sworn enemies for centuries, with only the Hanzo Hattori truce maintaining a tenuous peace between the two families. But years later, when former shogun Ieyasu Tokugawa faces a dispute to determine which of his two grandsons shall succeed their father, he decides to settle the matter through a proxy war. Selected to represent the respective candidates, the Kouga and Iga send 10 of their best fighters into a deadly battle, with the winning party deciding the rightful successor. Thus, the truce is revoked and the ruthless bloodshed begins.

But not all approve the truce's end. Gennosuke of Kouga and Oboro of Iga were to be married in hopes of ensuring lasting peace. However, unlike typical arranged marriages, they were already deeply in love. As preparations for the war ensue, Gennosuke questions his loyalties while Oboro refuses to fight. Fueled by their reawakened feud, will the two clans be consumed by hatred, or have their destinies changed by genuine love?