After chasing down a Giant Gamma in the Iguana Ghostriker, Takeru discovers Akari and Onari have been kidnapped by Gamma Commandos. When going to save them, Takeru encounters Makoto and the mysterious figure known as Saionji, who reveals he knew Takeru's father Ryū and that he had been involved in an experiment. What is the experiment? And what does it have to do with Makoto as Kamen Rider Specter?