When Ryotaro and Momotaros are injured in a fight with an Imagin, Kotaro, Kamen Rider New Den-O, and his Imagin partner Teddy return to help solve the case of a stolen ticket and the mystery of a young woman’s doppelganger! But Owner shatters their partnership when he creates a new contract with Teddy, as the Mantis Imagin rampages! Can Kotaro overcome his loss and discover the truth behind the two Mikus?

With Kai’s defeat, Ryotaro and the rest of the DenLiner crew resume their time-traveling adventures by founding a detective agency to keep any other surviving Imagin in check. But when a rogue Imagin swipes Owner’s spare Den-O Pass, it’s up to the DenLiner Police and rookie detective Kazuya, along with a little help from another Rider, to stop the evil Imagin and save the past, present, and future!

When the Imagin and Kohana take a trip to visit Ryotaro and Airi, they are attacked by the legendary Ghost Train, and onboard are two Imagin and the evil Kamen Rider Yuuki, who is none other than Ryotaro! But when all hope seems lost, a blue DenLiner appears, delivering someone claiming to be Kamen Rider New Den-O! Just who is he, and can he help everyone save Ryotaro and save time once again?

With Gaoh having stolen the DenLiner and trapping the Imagins onboard, Ryotaro and Hana find themselves trapped in the year 2000 where they meet Ryotaro’s younger self, but Ryotaro is slowly forgetting everything having to do with Den-O! As Gaoh gets closer to his target, the only hope lies with Yuuto’s complex plans and a little bit of luck, or else time itself could fall victim to Gaoh’s evil desires!

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.

With the older Sakurai having sacrificed himself to ensure Airi’s future, Yuuto struggles with his own role in their story. Despite being told that he is no longer bound to his future, Yuuto finds himself continually drawn to Airi, and when another man contracts with an Imagin to woo her, Ryotaro and the Imgain are pulled into the situation, all while the DenLiner runs out of control through time!

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?!