The Hikari Studio arrives in a new A.R. World where, after seeing that Tsukasa’s photos of this world are coming out perfectly, Natsumi realizes they may be in Tsukasa’s home world. Finding a mansion depicted on the backdrop that took them here, Tsukasa and company enter and meet a girl named Sayo, who identifies Tsukasa as her older brother. Tsukasa still cannot remember as Sayo’s caretaker Nobuhiko Tsukikage arrives to tell that Tsukasa’s arrival has distorted the world and this can only be fixed by the strongest Kamen Rider existing in this world.

After his memories return, Tsukasa orders Nobuhiko to summon every Rider for a tournament to determine the strongest one. After numerous matches, it comes down to a 6-man tag team match between the team of Decade, Kuuga, and Diend vs. V3, BLACK, and Super-1. Upon victory, Tsukasa and company end up into a giant castle with Yusuke and Natsumi finding themselves in the throne room surrounded by monsters. Eijiro appears shortly after, only to reveal himself as Doctor Shinigami. Yusuke and Natsumi learn that they are in Dai-Shocker’s base of operations as the organization welcomes Tsukasa’s return as Dai-Shocker’s leader.-http://en.wikipedia.org/wiki/Kamen_Rider_Decade:_All_Riders_vs._Dai-Shocker