Utterly normal middle school student Ittoki Sakuraba is fed up with having to take lessons every day and being monitored by childhood friend Kousatsu. Then one day, a beautiful girl named Tsubaki confesses feelings for him.

Ittoki heads off to settle scores with Onimichi and Onimichi sends all his forces to Iga to exterminate the Iga villages. The final battle of the Shinobi begins.