Thanks to an age of constant war, the Iga and Kouga had independently achieved an expansion of their respective forces. Both shinobi forces, owing to that long history of warring, shared an antagonistic relationship of mutual hatred towards one another. However, during the ninth year of the Tenshou era, the Iga forces fell into ruin due to the Tenshou Iga War started by Oda Nobunaga. The few Iga members that had survived were taken in by the Kouga forces. Seventeen years later, the Sengoku period had ended and lasting peace came to the world. Dreaming of performing shinobi duties, Ueno Enju (the protagonist), daughter of the Kouga forces' leader, Ueno Kandou, had been training everyday. After finally being selected to go on her first mission, a major incident occurs. It not only derails Enju's fate, but the fate of the village as well... [Translation of the official website's story summary.]