The heiress to half of the Yakuza crime syndicate forges an uneasy alliance with an amnesiac stranger who believes an ancient sword binds their two fates. She must unleash war against the other half of the syndicate who wants her dead.
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.