As Kamen Rider Ouja is about to strike a helpless Shinji, Kamen Rider Knight appears and blocks the attack. Ouja then joins the fight with Kamen Rider Gai and Kamen Rider Scissors, while Knight tells Shinji to run. However, the two are stopped by Kamen Rider Raia, who has already betrayed Shinji in the previous episode. Kimura flees from the chaotic battle. Kamen Rider Zolda uses his Final Vent, causing an enormous explosion, forcing the combatants to retreat.
In a dimension full of broken mirror pieces, Shinji finds Dark Shinji, with the latter urging the former to merge with him so that "they" can win the Rider War. As Dark Shinji gets closer and closer to Shinji, making him terrified, the latter wakes up and realizes it is all a dream.
Shinji finds himself in a parking lot with Ren Akiyama. Ren knows Shinji's name, but Shinji mispronounces Ren's name as "Ron", just like in the past. The two wonder whether they have met before or not, with Ren not having any clue on the matter. Shinji thanks Ren for saving him earlier, but Ren states that he does not save Shinji because they seem to know each other. Instead, Ren remarks there is a voice in his head which keeps telling him to stop the Rider War. Shinji responds he also wants to meet a certain someone who has been appearing in his dreams ever since day one. He then asks whether Ren knows anything about the past, which ren admits he also has no clue about. Shinji voices his approval of Ren's goal to stop the War. Ren thinks Shinji just wants to stop the War because he is afraid of losing, which Shinji dismisses. Shinji then offers Ren a drink, which he has had with him since the battle at the beginning of the episode, only for Ren to spew the content on his face. Shinji states that the two may not be very close in the past, to which Ren agrees. As Takeshi Asakura is the only one with memory still intact, the two decide to go and meet him.
In another place, Ishihashi, Jun, and Tezuka are preapring a barbecue. Ishihashi asks Tezuka for some spices to eat with his steak, only to be stabbed by the latter with a knife. He grabs Jun's hand for help, but he is stabbed another time by Jun. His body then disintegrates. Tezuka and Jun later have sex in private.
It is the 6th day of the Rider War, Asakura is seen eating some food prepared by Goro. Asakura is pleased by the food, but he still wonders why Goro is even serving him. He even remarks that Kitaoka may "turn in his grave" if he knows Goro is serving his archenemy. Asakura states he has never actually hated Kitaoka, but, rather, Kitaoka hates him. He then tells Goro that hatred is a thing that "can be trusted". Ren and Shinji come and ask Asakura about their past. Ren voices his distrust towards the mysterious woman's words, and that even if there is a winner, it will still be meaningless if no one can get out of the Mirror World. Asakura only laughs, and says that their past is fighting and killing each other, and it is their destiny to keep fighting like that for eternity.
After having sex, Tezuka states that eventually, he and Jun will have to fight each other to decide the winner. Jun laughs, responding that killing each other is also a passionate way of expressing love, but he also adds that he does not wish to fight Tezuka. In the bathroom, Tezuka encounters Dark Shinji. Dark Shinji tells Tezuka that the traitor will eventually be betrayed, and that he should eliminate Jun to ensure his own safety. Later on, Tezuka and Jun fight against each other, with Jun disgusted at the betrayal. Raia uses his Final Vent and attempt to finish Gai off, but Gai counters with a Confine Vent and his own Final Vent, mortally wounding Raia, knocking him out of the transformation. Upon receiving the fatal blow, Tezuka starts to regain his memory, and his previous friendship with Shinji. He leaves the place to look for Shinji.
Elsewhere, an outraged Ouja is looking for Shinji and Ren, telling them to entertain him more and more. He starts striking random objects in frustration, but the two are still nowhere to be found.
Shinji and Ren retreat to an abandoned house, with the former remarking that Asakura is not the type that can be reasoned with. The mysterious woman appears before them and declares that the time remaining is one day. Both Shinji and Ren are irritated, asking the woman why she is doing all this. The woman starts to tell the two Riders her story: She is a woman named Sara. In the past, a man named Tatsuya Kano hits her with his car, putting her into the hospital. The man would then visit her frequently in the hospital, and the two start dating each other. However, the injury from the accident still does not allow her body to recover completely, and she is put back into the hospital again. Tatsuya, not wanting to lose her, becomes Another Ryuki and starts killing countless people in the real world in hopes that the lives he kills will be able to resurrect her. Not wanting Tatsuya to kill more people, her Mirror self restarts the Rider War. Because the real world Sara only has one day left to live, she says one day is the time remaining for the winner to be found. Shinji still wants to know more, but the woman vanishes.
Kimura brings a deceased Tezuka to Shinji, telling him that Tezuka has finally regained his memory just before dying. He relates Tezuka's messages to Shinji: That Shinji should still be himself, and that he should be careful of "another Shinji". As Tezuka's body disintegrates, Dark Shinji suddenly appears, and merges with the real Shinji.
Elsewhere, Jun is still looking for Tezuka, demanding him to come and "accept his love". Dark Shinji stops Jun on his way, saying that Tezuka is dead, and that he will "love" Jun in his place. Dark Shinji transforms into Kamen Rider Ryuga and effortlessly defeats Kamen Rider Gai. He kills Gai using his Final Vent, stomping his foot on Jun's body as it disintegrates. Ren and Kimura, having witnessed the whole event, are shocked and horrified.
Episode Tropes:
- Asshole Victim:
- Ishihashi is backstabbed by his teammates right after he brags about how easy it was to deceive everyone else and steal their decks.
- Jun gets his comeuppance against Ryuga, and dies with nobody mourning him.
- Demonic Possession:Dark Shinji merges with the real Shinji, turning the latter evil.
- My God, What Have I Done?: In his last moments, Miyuki regains his memories from the previous Rider War, and expresses regret for joining Jun's side and betraying Shinji.
- Out of Focus: Once again, Sougo and Geiz have minimal plot relevance, only seen watching Another Ryuki's rampage while unable to stop him.
- The Reveal: Everything regarding the Rider War is revealed. Sara started the Rider War in order to find somebody to stop her boyfriend, Tatsuya (Another Ryuki), from his mass murder spree in order to revive her.
