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.
Ninja is a 2009 American martial arts film directed by Isaac Florentine and starring Scott Adkins, Tsuyoshi Ihara and Mika Hijii. The film's plot revolves around an American martial artist named Casey Bowman, who is asked by his sensei to travel to New York City and protect the Yoroi Bitsu, an armored chest that contains the weapons of the last Kōga ninja.