45 years ago, a man was subjected to the experiments of the secret organization Shocker and became a cyborg. Since that day, the man's sole mission has been protecting humanity and justice from the threat of Shocker. His name is Takeshi Hongo, the first Kamen Rider. After a long battle overseas, Hongo hears a certain girl is in danger and immediately returns to Japan. He then meets Takeru Tenkuji, Kamen Rider Ghost, who had been investigating the girl's whereabouts.

Brother and sister are drawn into a thrilling game of survival, in which they use a bizarre device called SCM to turn others into their slaves.