A sinister Ace transforms into Kamen Rider Dooms Geats, clashing with allies. Beroba, another Ace, awakens Michinaga's might. The Riders unravel the enigma surrounding the two Aces to thwart the God of Destruction's advent.

Sometime has passed since Ace Ukiyo ascended as a "god" and became the overseer of the peaceful world he left behind. However a single bullet tears through that peace, and a mutant breed Jyamato appears. The appearance of this particular Jyamato is capable of causing the extinction of humanity, with no one realizing that this is the harbinger who gave rise to the God of Destruction itself, the God Jyamato. Then a white-haired Ace appears, who then transforms into Kamen Rider Dooms Geats and attacks both Tycoon and Na-Go. Just when everyone is confused, another Ace appears. Meanwhile Beroba approaches Michinaga and awakens the dormant Jyamato powers inside of him. Just what is the ominous power that this Buffa possesses? Also what is the truth behind the existence of the "two Ace Ukiyos"? As the birth of the God of Destruction approaches every moment... just what will the Kamen Riders do in order to protect this world and humanity!?—Johnny Company