The master ninja Ryu Hayabusa is summoned to London to confront a terrorist group led by a mysterious masked alchemist known as the Regent of the Mask, who has specifically demanded that the legendary Dragon Ninja face him. During their clash, the Regent lays a sinister curse upon Ryu's right arm, one that feeds on the lives he has taken and threatens to slowly consume him. The alchemist then issues an ultimatum, giving the nations of the world only days to surrender or be destroyed. Bearing the curse and the weight of the coming threat, Ryu sets out across the globe to stop the Regent and his followers.