Ten years ago, a bloody crack suddenly tore through the sky, and then monsters called strange demons descended to cause harm to the world. In order to cope with the crisis, humans used the power of strange demons to create spiritual keys, and gradually wiped them out, but the cracks still hung in the sky... Years later, the resurrected strange demons attacked again, and a pair of young people transformed into Kamen Riders and stepped out, but during the battle they gradually discovered the cruel truth of the world...
