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.
The story begins when Geki Red battles Nunchaku Banki after returning from his trip around the world for Natsume's birthday, with Geki Yellow and Geki Blue arriving to provide backup. After sending the Gekirangers into another dimension, the Go-ongers arrive before the Savage Machine Beast departs after his quarry. After clearing a misunderstanding with Geki Violet and Geki Chopper, the two bring them to SCRTC to see Master Xia Fu, with Hant revealing he met Miki at one of his past jobs at the Kyoryuya Curry Shop.
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 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!
Bent on the destruction of the human race, the secret underground organization Shocker secretly planned to plunge the world into chaos. But they didn’t count on the revolt of both of their experimentally “reconstructed” human beings, the Kamen Riders. Two years after their first battle with Shocker, a 3rd Rider arises to confront them, known only as “Version 3.” The arrival of the third Kamen Rider will hurl the heroes into their most terrible battle yet and the fate of the world hangs in the balance.
Takeshi Hongo is a man of extraordinary intellect, but his promising future is about to be maliciously snuffed out by and evil secret society known as Shocker. Reinvented against his will and transformed into a powerful experimental cyborg, Hongo will forever be known as Kamen Rider The First.
The shock of her fiance's sudden dissolution of their relationship causes university student, Miki, to lose her voice. While recuperating in a hospital in her hometown of Hakodate, she learns of the tragic life of her deceased mother, Kaoru, from her grandmother.
Young art student Hideo paints an unnerving portrait of Tomie, who whispers that she loves him. Inexplicably, he reacts by stabbing her to death with a painting trowel. Two friends, Takumi and Shunichi, arrive on the scene and help him dispose of the body. To cheer him up, the boys take the unwitting murderer to the nearest bar for a party... but a mysterious girl named Tomie shows up, bearing a few odd physical resemblances to the dead girl in the ground.