Episode 0 : Rider of Humanity

In the city of Matan, a chemical scientist is kidnapped by anarchists bent on destroying all sense of order in the world. They force the scientist to make Pandorax, which splits Matan into three distircts ; Tavan, Kavan and Savan. From the Pandorax chemical comes monsters known as Smashers, who terrorize the people in these districts. The son of the kidnapped scientist, Benjamin Offton, is finally ready to fight against the anarchists, who refer to themselves as Smash, as he becomes Kamen Rider Build!