It remains as true today as it did in the days of the ancient Samurai: the weapons of the Ninja hold legendary powers for both good men and evil. The deadly weapons of the last Koga Ninja have now been entrusted to an American Ninjutsu student studying in Japan. Commanded by his Sensei to return to New York and protect the weapons at all cost, he must defeat the skilled Yakuza assassins hunting him and prevent the power of the weapons from falling into evil hands.
Fight everyone and trust no one: it's the code of survival practiced by martial arts master Casey Bowman (Scott Adkins) after his life of domestic bliss is shattered by a savage act of violence. With the help of his friend Nakabara (Kane Kosugi), the fearless American retrains his responses and elevates his battle skills to seek justice for his wife's murder. Casey stealthily tracks the man responsible on his mission of vengeance, but just when he has his prey cornered, an unexpected twist him to see even those closest to him as enemies. In the ultimate confrontation, Casey must reflect on his teachings to become an invisible warrior worthy of the title Ninja.