Taking place after the events of series, the Tarōs and Kohana go out of the DenLiner for a day to visit Ryotaro and Airi after their parting in the aftermath of their battle with Kai. However, they see the mysterious Ghost Train that has been mentioned in urban legends as Momotaros and gang are then attacked by two evil Imagin and Kamen Rider Yuuki Skull Form. During the fight, it is revealed to the Tarōs that Yuuki is none other than Ryotaro possessed by an evil Imagin. Even with Zeronos coming to the gang's aid, things seem bleak until a blue DenLiner appears with a new figure: Kamen Rider New Den-O.
Ryotaro pursues the Molech Imagin to May 8, 2000. Though Den-O Sword Form destroys the Molech Imagin, the Imagin fulfilled his mission as the DenLiner ends up hijacked by the rest of the Imagin led by a rogue Kamen Rider named Gaoh. After stealing Owner's Master Pass and trapping Urataros and Kintaros, Gaoh forces the DenLiner to travel back in time via "God's Line" to the Edo Period of Japan so he can retrieve the legendary God's Train, the GaohLiner.
Set after the events of Kamen Rider Den-O, Ryoutaro and the DenLiner gang have set up a detective agency called the DenLiner Police who seek to keep the Imagin that survived the Junction Point in check after an Imagin stole a spare Den-O Pass from Owner while he was training.
Taking place after the events of Kamen Rider Decade episode 15, under the impression that they saved the World of Den-O, Tsukasa Kadoya 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 out with the true threat to their world.
The course of history is accidentally changed when Ankh leaves behind a Medal in the past after Kamen Rider OOO helps Den-O and New Den-O chase a Mole Imagin all the way back to November 11, 1971. When they return to the present time on April 1, 2011, they discover that Shocker succeeded in conquering the world and now Kamen Rider 1 and 2 are Shocker's top agents. In order to defeat Shocker, Kamen Rider OOO and the Den-Liner gang must travel back in time to gather other Kamen Riders to defeat Shocker and restore the proper timeline.
Ryotaro Nogami, Kohana, Momotaros, Urataros, Kintaros, Ryutaros, Deneb, and Sieg join in on a series of exercises to get Ryotaro into shape so he can fight. Unfortunately, the Spider Imagin, the Wolf Imagin, and the Anthopper Imagin interrupt the exercises, Ryotaro becomes Kamen Rider Den-O Liner Form to use his training against the evil Imagin!
Episode Yellow: Treasure de End Pirates focuses on the cyan-colored Kamen Rider Diend, who only has minor yellow accents on his suit and a yellow Diend Kamen Ride card. The story features Daiki Kaito traveling to the World of Den-O again and his involvement in the theft of the DenLiner and Rider Pass, the result of being possessed by the Spider Imagin. He is chased after by Reiji Kurosaki as Kamen Rider G Den-O for his crimes against the timeline.
A series of net movies to promote the Kamen Ride movie "OOO, Den-O, All Riders: Let's Go Kamen Riders". 48 shorts were released with each webisode focusing on a Kamen Rider that matches a specific Zodiac sign and a blood type.The webisodes are alternatively hosted by Sieg, Momotaros, Kivat and Urataros. After each segment, the host explains the featured Kamen Rider's horoscope, determining which other Rider he is most compatible with and which one he is not, as well as which Riders are compatible with women of the webisode's specific Zodiac sign and blood type.
Episode Blue: The Dispatched Imagin is Newtral features the blue-colored Kamen Rider New Den-O. The story is themed around "Friendship" and features Den-O and New Den-O attempting to regain control of the DenLiner (having lost it in Episode Red) when an Imagin takes it over, as well as two mysterious men. Throughout, Kotaro's and Teddy's friendship is tested and strengthened.
Episode Red: Zero no Star Twinkle is described as a love story and it focuses on Kamen Rider Zeronos, particularly his red Zero Form. The story is that of the younger Yuto Sakurai trying to ensure that the timeline is preserved when a new suitor comes to woo Airi Nogami, his older self's fianceé, but when Momotaros comes to ask for help he is torn between his two conflicting attempts to preserve time and space.