The Smart Brain corporation, the world's most powerful corporation, is trying to take over the world using Orphnoch. Referred to as the "next stage in humanity's evolution", they plan to covertly kill off the human population and replace them with their Orphnoch, having randomly seeded people with DNA to turn them into Orphnoch. In pursuit of this goal, they develop three suits of power armor, called Rider Gears: Delta, Faiz, and Kaixa. The Rider Gears are stolen by Hanagata, the former chief of Smart Brain, who sends them to his foster children so they can stop the Orphnoch and Smart Brain from achieving their goal. A young loner, Inui Takumi, is unwittingly drawn into the conflict between the Orphnoch and humans, becoming Kamen Rider Faiz to save the life of Sonoda Mari, one of the foster children. As a result, Smart Brain begins targeting him in an attempt to retrieve the Faiz Gear.