- Written by: Nobuhiro MouriDirected By: Takayuki Shibasaki
In a field, Sougo as GrandZi-O is facing Another Den-O. He utilizes the final form's ability to summon Kamen Riders: Build, Kuuga, OOO and Gaim to attack the Another Rider as Woz exclaims that Sougo has now inherited the powers of all Heisei Riders. In the meantime, two mysterious persons are observing the battle, noting that finally, the Overlord of Time is here.
That said, two mysterious individuals are stalking Sougo Tokiwa.
Whomever could they be?
Let us return to a time when two Watches remain to be found...
Meanwhile, the train of time DenLiner is crashing at 2019 Japan, with the Imagins bickering...
The very same Kamen Rider Den-O whose power Sougo Tokiwa will soon claim.
The Imagins are crashing at 9 5 DO when they request Junichiro Tokiwa's aid at repairing the DenLiner. It seems that the uncle is considered the best repairman of this era. Junichiro said that he only repairs clocks, but Urataros explains that the DenLiner is just like a giant clock, inciting his curiosity. Junichiro is still hesitating, however, but Ryutaros possesses him and alongside the other Imagins, they go to DenLiner, with a concerned Sougo in tow.
Somewhere in the city, Ora meets Heure to discuss the situation regarding Sougo now, as he only needs 2 more Ridewatches to ascend as Oma Zi-O, foiling the Time Jackers' plan. Ora claims that she has a way to deter this, however.
At a cemetery, Yukihiro Osumi is seen mourning at his girlfriend's gravestone. He is then approached by Takuya Endo, who lashes out at him, saying that Yukihiro is the one responsible for his sister's death. Suddenly, Ora appears and offers Takuya a chance to change the past, but for that, he must help her steal the DenLiner. Takuya is transformed into Another Den-O and escapes with Ora as Yukihiro can only cower in terror. Then, a Mole Imagin appears before him. The Imagin asks what Yukihiro's wish is, and he answers that he wants to help Takuya. With that, the contract is forged.
At the DenLiner, Junichiro notes that it indeed operates just like a giant clock. So, he will endeavor to repair it. Suddenly they're attacked by Another Den-O. Sougo, Geiz and Woz transform into Zi-O Trinity... only to intercepted by ZeroLiner, driven by Yuto Sakurai and Deneb. Sougo mistakes Yuto as Kyosuke Kiriya, but he transforms into Kamen Rider Zeronos to defeat Sougo, that he proclaims as the tyrannical Overlord. After a brief scuffle, they find that Another Den-O is still attacking the DenLiner, so they combine their attacks to defeat him. The Another Rider reverts back into Takuya and Ora helps him escape.
Back in 9 5 DO, Yuto explains that he and Deneb are from the future. Having witnessed the rise of Oma Zi-O after Sougo collected all 20 Ridewatches, they travel back in time to stop him. After that, Yuuto and Deneb leave the shop. As Sougo is confused, Momotaros possesses Geiz because he wants to defeat Another Den-O by himself. He went outside with a panicked Tsukuyomi chasing him.
Meanwhile, Sougo is still brooding. He initially wanted to collect all Ridewatches to defeat Oma Zi-O himself, but as Yuuto said, he will become the Overlord instead in that event. Woz reassures him, as to defeat Oma Zi-O, Sougo must stand on the Overlord's level himself, which is by gaining the same power as him. With this resolve, Sougo and Woz depart.
Another Den-O is on a rampage to find the DenLiner. Momotaros, in Geiz's body, arrives to fight, but he doesn't know how to transform using Ziku Driver. Tsukuyomi helps him, and he transforms into GeizRevive Goretsu. He fights Another Den-O valiantly, but the Mole Imagin disrupts him as he wanted to fulfill Yukihiro's wish. Then, Sougo and Woz arrive, wondering about the Imagin. Yuto also arrives and challenges Sougo once again, but the future Overlord states that he still wants to ascend no matter what, as he aims to become a revered and benevolent king. Sougo transforms into Zi-O Trinity, dragging Momotaros inside the Fusion Rider as he had possessed Geiz.
Sensing Momotaros inside Zi-O, Yuto transforms into Zeronos Vega form and a free-for-all battle begins. In the end, Zi-O Trinity defeats Zeronos, but as he moves to Another Den-O, the repaired DenLiner arrives. In the midst of confusion, Another Den-O hijacks the train of time and he escapes into another point of time. The Mole Imagin, declaring Yukihiro's wish "fulfilled", then goes inside of his contractor.
Zi-O Trinity cancels the transformation and Geiz immediately grapples with Momotaros in annoyance. Sougo notes that they don't know the arriving point of DenLiner, as Woz answers that they need the Den-O Ridewatch for that. Momotaros gives him said Ridewatch as he and his fellow Imagin had already created it, and it resonates with other 19 Heisei Ridewatches to form the GrandZi-O Ridewatch, as the others (except Woz and Momotaros) witness in horror...
Episode Tropes
- All Your Powers Combined: Grand Zi-O has the ability to summon Riders simply by touching a statue of them on his armor. It should be noted that Sougo isn’t summoning the Riders, so much as opening portals in time to make his enemies relive the events of the Riders in question. Examples include OOO's Scanning Charge Kick involving with the stone pillars summoned by the Monster of the Week and Gaim's background of the first time he transformed and slayed the Byakko Inves. Additionally, the Grand Zi-O Ridewatch is created when Sougo is given the Den-O Ridewatch, resonating with the other 18 Heisei Ridewatches kept in 9to5Do and bringing them all together to merge into one entity.
- Beyond the Impossible: The Taros approach Junichiro in order to find help to repair the DenLiner, to which he rejects because it was understandably out of his expertise. Not only does Junichiro manage to fix the DenLiner, he even gets to ride the DenBird to drive it.
- Demonic Possession: As per usual, the Taros inflict this on whoever they happen to inhabit, with their victims this time being Junichiro by Ryutaros and Geiz by Momotaros.
- Gotta Catch 'Em All: Subverted. After Sougo gets the Den-O Ridewatch, he still has to obtain the Drive Ridewatch himself to complete the Heisei set. Despite that, the 19 powers he has already obtained fuse together into the Grand Zi-O Ridewatch, likely using Geiz’s Drive Ridewatch from the future as a temporary substitute and still requiring Sougo to obtain Drive's powers in the present for it to last.
- Identical Stranger: Sougo notes the uncanny resemblance between Yuto Sakurai and Kyosuke Kiriya (they're both played by Yuichi Nakamura), but Yuto insists that Sougo is mistaken.
- In Medias Res: The episode opens with the debut of Grand Zi-O, and Yuto Sakurai resolving to deal with Sougo himself after seeing what Grand Zi-O is capable of.
- Kick the Dog: Takuya blaming Yukihiro for his sister's death is one thing,
but refusing to let Yukihiro pay his respects to her and throwing away the bouquet of flowers he had placed on her gravestone was uncalled for. - MacGuffin Delivery Service: While Zi-O Trinity was busy dealing with Zeronos Vega form, Another Den-O uses the opening to invade and hijack the DenLiner, defeating the Taros on board in the process.
- What the Hell, Hero?: Geiz is really pissed off at Momotaros for hijacking his body and attempts to strangle him.
