Aka Kage, Aoi Kage and Asuka are trio of ninjas sent to perform dangerous secret missions for their master. Although Aka and Aoi are both in love with Asuka, the friendship built from their years of training together prevents any jealousies from forming. When Asuka is killed during a mission, however, the heartbroken Aka and Aoi both go their separate ways before returning to avenge their friend's death.