Summary: A mysterious object known as the Pandora Box was brought back from Mars.
In effect, Japan was divided into three by giant walls produced from
the box. 10 years have passed since that day. This story takes place in
one of the city capitals, Touto. Mysterious organisms known as Smash are
terrorizing humanity. A physicist saves people from the Smash and
pursues the mystery hidden within the Pandora Box. His name is Sento
Kiryu. People call him... the Kamen Rider.