A westerner named Casey, studying Ninjutsu in Japan, is asked by the
Sensei to return to New York to protect the legendary Yoroi Bitsu, an
armored chest that contains the weapons of the last Koga Ninja.

Ninjutsu is the ancient martial art of the ninja's. It is a fighting style full of questions and mysteries, a source of mythe and a whole bunch of movies. Although a lot of people don't know exactly what ninjutsu really is, besides a lethal fighting style

Masters of espionage and silent killing techniques, their training was so extreme that other warriors often classed them as a type of one-man army. Students eligible to learn this art were picked from the cream of the Hwa-rang-do ranks.