The story takes place in Japan in the early 17th century, shortly after the start of the Edo period. Ieyasu Tokugawa had won the Battle of Sekigahara and was about to take control of the country when Sasuke Sarutobi, a ninja boy in the service of Yukimura Sanada, Lord of Shinano, rose up with his companions, Iron Monk and Saizo Kirigakure. To protect the lord from him, Sasuke and his men began a battle against the ninjas of the Iga Ninja Army, who sought to end their lives.