家族を犠牲にしても英雄の道を貫こうとした香川に、ますます傾倒する東條悟。一方、神崎士郎の謎を追って、香川研究室をかぎまわる令子。そんな彼女を排除しようとする悟と対決する北岡。そして、仮面ライダーインペラーを名のる謎の青年が暗躍を始めた。
Tojo finds out that Kagawa has his own family, much to the dissatisfaction of Tojo himself.
Asakura attempts to find Tojo by asking Kitaoka, and later Shinji.
Kitaoka finds Room 401, the room where Shiro Kanzaki worked.
Having learned the secrets about the Mirror World, Tojo attempts to kill Reiko.
Mitsuru Sano reveals himself to everyone as Kamen Rider Imperer, offering his services as an ally for cash.