- Title: OOO, Den-O, All Riders : Let's Go Kamen Riders
- Alternative Title: オーズ・電王・オールライダー レッツゴー仮面ライダー Ōzu Den'ō Ōru Raidā Rettsu Gō Kamen Raidā
- Number of Episode: 1
- More Info: https://en.wikipedia.org/wiki/OOO,_Den-O,_All_Riders:_Let's_Go_Kamen_Riders
- Smmary: On April 1, 2011, Kamen Rider OOO finds himself battling three Mole Imagin, unaware they are Imagin until Ankh arrives to confirm that the monsters are not Yummies. The three Imagin see a boy and jump into him to escape into time before the DenLiner suddenly appears. Kotaro Nogami and Teddy emerge from the train to pinpoint the Mole Imagin's destination to be November 11, 1971, confused on how the boy's memories exceed that far in time. When Ankh demands answers, Teddy explains who he and Eiji Hino are to Kotaro, who then introduces himself while explaining their mission to deal with the rogue Imagin who would disrupt the flow of time. Ankh has Eiji join him in getting on the DenLiner as it goes back in time, warned by the DenLiner's Owner to stay on the train so not to disrupt time.
Once at 1971, as Kamen Rider New Den-O eliminates two of the Mole Imagin with the third one still on the run, Ankh manages to leave Shingo's body to get out of the DenLiner to enact his plan to steal the Core Medals from the other Greeed while they are still sealed. Realizing this, Eiji goes after Ankh before they run into the Mole Imagin as New Den-O destroys him. The Taros manage in capturing Ankh before taking him and Eiji back to the present. However, as the DenLiner departs, it turned out that one of Ankh's Cell Medals was dislodged from the Mole Imagin's death and was found by a Shocker Combatman as he presents it to General Black.
The DenLiner arrives in the present to drop Eiji and Ankh off, with the latter feeling that something is off. The two then meet the boy from before, Naoki, as he and his friend, Mitsuru, tried to steal Eiji's underwear. Though Ankh saw through it, he realized they stole his O-Medal Case and chases the boys down to the slums where the case is passed on to other children. The chase is disrupted by the police, who reveal themselves as members of Shocker as they try to arrest Eiji and Ankh. After escaping from the police and meeting at the Snack Amigo, where the Cous Coussier is supposed to be, Eiji finds the kids from before. Confused about this "Shocker" group everyone mentions, Ankh arrives and explains to Eiji that he researched Shocker and learned that they are a terrorist organization who managed to gain control over Japan. Soon after, as Ankh holds one of the kids hostage to get the Core Medals back while Eiji manages to calm everyone down before, an announcement starts that Shocker has been inducted into the United Nations and has incorporated the various organizations (G.O.D., Geddon, the Delza Army, Gorgom, the Crisis Empire, and the Museum) to begin their world domination plan and mass extermination of all remaining normal humans.
When the Shocker Police arrive, Eiji, Ankh and the children run for it before Shigeru is held hostage. With Mitsuru and Naoki abandoning Shigeru as their only choice, Eiji refuses to leave the boy to die as he becomes Kamen Rider OOO to battle the monsters and cover the boys' escape. However, Shocker's elite soldiers, Kamen Riders 1 and 2, arrive and proceed to beat him. Though Mitsuru is reluctant, the boys give Kamen Rider OOO back the Medal Case. Kamen Rider OOO changes into Latorartar Combo to blind them so he can rush the children to safety. However, they are ambushed by General Shadow as he proceeds to defeat Kamen Rider OOO. Fortunately, the DenLiner arrives and picks Eiji and the children. Eiji learns from Teddy that Shocker found a Core Medal in 1971 and modified it for their use. Though the created Shocker Medal was powerless on its own, the Cell Medal Ankh left behind enabled Shocker to create the Shocker Greeed, which swiftly defeated the first Kamen Riders so they would become Shocker members as originally intended. This act in turn negates the existence of all Kamen Riders after the first Kamen Riders and allowed Shocker to continue its evil. Though Eiji offers to help, Kotaro tells him that he will correct the timeline, leaving him and Shigeru in the slums where they meet the Hina Izumi of this timeline. Finding Mitsuru and Naoki still on the train, the gang finds Ankh as well, putting a lease on him so Momotaros would make sure the Greeed would not mess up time any further.
Arriving one minute before their previous arrival, hiding until the events unfold, Kotaro recovers the Cell Medal. However, upon attempting to reclaim his Cell Medal, Ankh to causes four Cell Medals to fly out the window with the everyone jumping out. Though Urataros, Kintaros, and Ryutaros managed to destroy three, the last one is found by a girl named Nokko, who mistakes Kotaro, Momotaros, Teddy, and Ankh as Shocker agents. She proceeds to her fellow Kamen Rider Scouts before the Cell Medal drops from her hands and is picked up by a Shocker Combatman who hands it over to General Black. Refusing to let history repeat itself, Kotaro becomes New Den-O as he and Momotaros battle the Shocker platoon while Mitsuru and Naoki run off with the Kamen Rider Scouts covering them as they and Naoki make it to a warehouse. They are attacked by Shocker's Inhumanoids before Kamen Riders 1 and 2 arrive to cover the kids' escape while they take out the Shocker soldiers. At that time, General Black transforms into the Inhumanoid Hiruchameleon to overpower New Den-O and Momotaros until the first Kamen Riders and the children trick Hiruchameleon into taking a fake Cell Medal with a transmitter so they can locate Shocker's headquarters and take out the organization's leader.
Before they proceed, New Den-O destroys the real Cell Medal to prevent any further trouble. However, once there, the Double Riders, New Den-O, and Momotaros realize that they have fallen into a trap as General Black reveals that the Cell Medal that Kotaro stole was a fake as the Great Leader creates the Shocker Greeed. General Black then calls out Ikadevil, Garagaranda, and other revived kaijin before changing into Hiruchameleon and battling the Riders. As New Den-O and Momotaros have their hands full with the Shocker Greeed, the Double Riders dispose of the revived kaijin and unmask the Great Leader. Outside, Turtle Bazooka fires at the DenLiner, forcing the Owner to order a retreat. The Double Riders tell Kotaro, Momotaros, and the boys to jump onboard while they cover their escape. Still wanting to help the Double Riders, Naoki jumps off the heavily damaged DenLiner with Teddy following him before it heads back in time.
On April 2, 2011, as the damaged DenLiner returns, Shocker initiates its mass extermination as Kamen Rider OOO fights them off before seeing the train. Assuming Tajadol Combo, Kamen Rider OOO takes Mitsuru to safety as Kotaro, Momotaros, and Ankh jump out of the train as it explodes. Losing his OOO Driver in the explosion, Eiji realizes that the DenLiner crew have failed in their mission and the train's destruction means the event cannot be undone. Soon after, Eiji and Kotaro are captured as Ankh and Momotaros (reduced to a floating left arm) cover everyone's escape. Arriving at the kids' spare hideout, the group soon find Teddy in his Macheteddy form as a grave marker along with a time capsule. Other than the Kamen Rider Scouts' uniforms and Core Medals, there is a letter from Naoki which details how he and the Kamen Rider Scouts became fugitives with Teddy sacrificing himself so they would escape. Surrounded by Shocker soldiers, Momotaros takes over Shingo's body and uses the Macheteddy to keep them busy while Hina and the children run off with the OOO Driver. However, M-Ankh is captured as well and is taken with Eiji and Kotaro for public execution.
However, with his group wearing the Kamen Rider Scout uniforms, Shigeru attempts to deliver the OOO Driver back to Eiji. By then, the Double Riders appear and reveal that a Shocker scientist has recently released them from their brainwashing, and they pretended to still be under Shocker's control until they crossed paths with the Shocker Greeed again. This turns into a revolt among the human audience as Eiji, Kotaro, and M-Ankh are freed. Receiving his OOO Driver from a mysterious man in white, Eiji changes into Kamen Rider OOO while Kotaro becomes New Den-O with the Momotaken sword. Though the four Kamen Riders are outnumbered at first, the playing field is changed with the sudden appearance of Kamen Riders V3, Riderman, X, Amazon, Stronger, Skyrider, Super-1, ZX, Black, and Black RX.
General Black demands the meaning of this as the Owner reveals that while the Kamen Riders were erased from time, they cannot be erased from the human heart. Soon, the DenLiner arrives with Kamen Riders Shin, ZO, J, Kuuga, Agito, Ryuki, Faiz, Blade, Hibiki, Kabuto, Kiva, and Decade. As Shotaro and Philip arrive to join the fight as Kamen Rider Double, Teddy appears with Momotaros tagging him in while becoming Kamen Rider Den-O. As Den-O assumes Climax Form to take out the grunts, Kamen Rider OOO destroys General Black with the Tatoba Kick. General Shadow attempts to escape, only to be halted by Kikaider, Kikaider 01, Inazuman and Zubat as the four destroy him.
While the Double Riders destroy the Shocker Greeed, Kamen Rider OOO arrives to the other Kamen Riders' aid as they are unable to attack the Great Leader. However, upon receiving the Shocker Medal from Ankh, who uses Momotaros to create the Imagin Core Medal, Kamen Rider OOO becomes Kamen Rider OOO Tamashii Combo and knocks the Great Leader over a far distance with the Tamashii Bomber. But as King Dark is about to fight the Kamen Riders, the Great Leader assumes his true form as titanic Rock Great Leader, using his power to attack the Kamen Riders while causing a fissure that consumes King Dark and the other surviving villains. The Kamen Riders are joined by Kamen Rider Birth and all of the extra Riders (except Another Agito, Dark Kiva, Danki, Eiki, Sabaki, Shuki, G, Abyss and every Movie, Special & Stageshow Rider besides those from Ryuki) to battle the new menace, jumping onto their motorcycles to execute the All Rider Break to destroy the Great Leader once and for all. In the end, after the Kamen Riders take their leave, the man in white appears before the group as Mitsuru identifies him as his father. Furthermore, the man is revealed to be Naoki and has lived in the past and married Nokko. He eventually became a Shocker scientist so he could undo the Riders' brainwashing. As the Imagin and Shocker Medals dissolve, much to Ankh's dismay, Eiji bids Kotaro farewell before the DenLiner embarks on its next destination.