Synopsis

After the end of the Pacific War, the first order issued by the GHQ (General Headquarters) upon occupying Japan was to dismantle the “ninja organizations.” As a result, it seemed that all the ninjas had disappeared, but in reality, they went underground, infiltrating various organizations around the world and operating in secret. One day, Kumogakure Kuro (Yamazaki Kento), a low-ranking ninja belonging to the ninja organization “NIN,” was bored with nothing to do. Suddenly, he was entrusted with an important mission to investigate the activities of a mysterious group known as “Under Ninja.”