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.
Kouta tries his hardest to convince Kamen Rider 1 that he wants to help out. Kamen Rider ZX, Ryo Murasame, who previously fought Badan in his own TV Special, will be returning to this movie.
Badan has also created their own Rider, Fifteen, in order to defeat the Kamen Riders. A mysterious man called Aoi Ren, played by Itsuji Itao, transforms into Fifteen. He uses a Sengoku Driver and Lock Seeds to fight, just like Gaim. Not only that, he’s using Legend Rider Lock Seeds. He even accesses Gaim Arms through the Gaim Lock Seed. The golden symbols on his head are actually the kanji characters 十五, which means Fifteen.
Source: Terebikun and TV Magazine (February-March)
All English translations are accredited to The Tokusatsu Network staff members. Please do not repost without crediting and directly linking back to the original Tokusatsu Network article.