What awaits Ace Ukiyo as he was called to participate in new yet special edition of the Desire Grand Prix, the "Desire Royale." Due to a mysterious game master working behind the scenes, the Kamen Riders clash with each other. A new and mysterious Rider also appears, and it erupts into an unprecedented war. Who will emerge victorious at the end of this fierce battle, and what is the wish that will the granted to the winner?