Unknown Title

The Riders are usually fighting in order to protect their worlds, but this time around they are fighting each other. It seems like the fighting is connected to the Underground Empire Badan. Kamen Rider 1, Takeshi Hongo, is trying to defeat Badan and in order to do that he must defeat Gaim. Badan are using monsters from different series and are trying to continue where Shocker left off. ToQger and Kyoryuger will be joining the fight to protect world peace.

葛葉紘汰 / 幪面超人鎧武正在調查存在於地球內部的另一個世界途中，遇上名為柊的少年正被地下帝國巴丹的怪人襲擊，此時被譽為傳說的男人 － 本鄉猛出現並對紘汰作出「像你這樣的菜鳥，我是不會承認你是幪面超人！」的宣言後，變身成為幪面超人1號將怪人擊倒。 過後與同樣正要尋找地下帝國巴丹下落的門矢士 / 幪面超人帝騎相遇，同時擁有歷代15名平成幪面超人力量的神秘戰士 － 幪面超人Fifteen，出現率領着地下帝國巴丹的怪人一眾大肆侵略，為了實行「MEGA・Reverse」的計劃更而擄走了柊。士及紘汰為阻止危機發生而結集歷代一共15名平成幪面超人，相反歷代15名昭和幪面超人卻不明目的出現面前敵對相向。超級戰隊一方的烈車戰隊特急者及獸電戰隊強龍者眼見事態嚴重而決定參戰。