After finishing his fight with Roidmudes and bidding farewell to Shinnosuke and crew, Go left wandering in the world and taking pictures of it. But two years later after the death of Chase he returns to Japan in search of an opportunity of a new Drive System. However, whole town suddenly became black due to large-scale power outage. Go quickly recalls the similar event. Is it Roidmudes?! But they were eradicated. Is it just a coincidence, or...? It's up to Go and Special Investigation Unit to cooperate in this case! Also, Go's first transformation to Kamen Rider Mach will be revealed!