The Ozunu Clan, led by the ruthless Lord Ozunu (Sho Kosugi), trains orphans from around the world to become the ultimate ninja assassins. One of these orphans, Raizo (Rain), was enrolled in the clan's brutal training to become its next successor. The only kindness he was ever shown was from a young kunoichi named Kiriko, with whom he eventually develops a romantic bond. As time goes on, Kiriko becomes disenchanted with the Ozunu's routine and wishes to abandon it for freedom. One rainy night, Kiriko decides to make her escape and encourages Raizo to join her; however he decides to stay. Branded as a traitor, Kiriko was caught and later executed in front of Raizo by their elder ninja brother Takeshi, impaling her through the heart. As a result of Kiriko's death, Raizo begins to harbor resentment and doubt towards the Ozunu. Some time later, Raizo is instructed by Lord Ozunu to complete his first assassination. Afterwards, Raizo meets the rest of his clan atop a city skyscraper in