Seorang ninja muda berpaling dari klan yang telah membesarkannya dan balas dendam atas pembunuhan keji yang mereka lakukan. Ia pun bekerjasama dengan penyidik dan mulai menghabisi musuh-musuhnya.
Ninja Assassin follows Raizo, one of the deadliest assassins in the world. Taken from the streets as a child, he was transformed into a trained killer by the Ozunu Clan, a secret society whose very existence is considered a myth. But haunted by the merciless execution of his friend by the Clan, Raizo breaks free from them and vanishes. Now he waits, preparing to exact his revenge.
