Tracking a mysterious man leaping through the night air of Tokyo, Ryotaro and the Imagins find themselves in November 2008, where the DenLiner is stolen by none other than Kaitou Daiki, Kamen Rider Diend! As Daiki tracks his past self, he faces off with Time Police officer Reiji Kurosaki, aka Kamen Rider G Den-O! Just what is the connection these two men share and who will prevail when the trigger is pulled?!
Under the impression that they saved the World of Den-O, Tsukasa Kadoya (Kamen Rider Decade) and company begin their journey to the World of Kabuto when they are halted by Sieg who presents them a manuscript that detailed the legendary Oni Conquest with Momotaros' image on it. As this occurred, the Tarōs mysteriously vanish from the DenLiner as they are about to help Kotaro Nogami (Kamen Rider New Den‑O) out with the true threat to their world.