Continuing from previous episode, Go can't still forgive the mistakes his father had made, even if it's turned out to be an accident. His wish is to destroy all Roidmudes before Kiriko would found out. At the Drive Pit, while Shinnosuke and Mr. Belt discuss the matters, Kiriko enters and reveals the Shift Speed Prototype Car in repair.
At the Special Investigation Unit's office, Shinnosuke deduced that the Roidmude's goal is to find a perfect candidate to fuse with and all rejected victims are currently in suspended animation. Strangely enough, Rinna was the only one remained unaffected. Mitsuhide Nira visits the office again, gleefully mocking over the team's ineffective ever since Shinnosuke was suspended before leaving. An idea hits Shinnosuke, where he and Kiriko visits Chase as they asks him for his help. While Chase agrees as a gift for saving him, he notes that Go's hatred for him earlier was unusual compared to before in addition with Seeker having anticipated/planned Go's ascending hatred so much that he wants to fight Chase. Kiriko tries to call Go but to no avail as he focuses in his client's help. Yoriko suddenly receives a call from Ryo, with his voice is shrouded but knows where the exact location he is as they rush there.
The Unit now knows that Go is the main target of Seeker Roidmude, while Jun speculates a greater force (presumably 001) is behind this threat. As 001 and Brain decide to launch the biggest move of all, Go and Yoriko arrives at an apartment area to search Ryo, where the whole residents descent into madness. Back at the Unit's office, Kyu reveals that Yoriko was never mentioned in one of Ryo's relatives. However, he manages to find the data about Ryo in his working area. Rinna enters and has upgraded the Heavy Acceleration detector to detect the smallest particle in a larger radius, even from the sky with same upgrades had been fitted to the Ride Booster Set.
What's left was for Shinnosuke's liberation. When Nira makes another visit, Shinnosuke and his comrades begged of lifting the liberation now for emergency, but Nira refuses to do so. Suddenly, Chase, under in guise as a Roidmude intrudes the Special Investigation Unit's office, holding Nira hostage. Being life-threaten, Nira decided to lift the ban on Shinnosuke's transformation as Drive. Proto-Zero and Drive goes out of the office, where Tridoron awaits as the Ride Booster Set fuses with Tridoron and Drive and Chaser aboard. Brain witness their depart, sending three Giant Bat Roidmudes to attack the Riders, with Drive and Chaser eliminate them before resuming their journey. After eliminating the Neo Viral Cores and knocking out the victims, Mach finds Ryo and awakes him but surprised when learns that Yoriko is not her sister.
Yoriko appears and reveals that she only uses Go's family relationship to target the population by spreading the madness infection that would cause them to go berserk, spreading through touch with Go affected as well. While 050/"Yoriko"'s plan indeed is to search for ideal hosts for the Neo Viral Cores, but the other plan they constructed is to draw his inner darkness. "Yoriko" as Seeker willingly had herself injured by Mach in order to escalate his anger until Chaser tried to stop him from his rage that would ended up killing "Yoriko", but eventually gets himself retaliated by Mach until Drive comes in and knocks Mach. Enraged by Drive's interference, Seeker tried to attack him, but overpowered by Type Formula and get separated, splitting into "Yoriko" and 050. In the end, Drive Type Formula Mantarn finishes 050 with Trailer Impact.
After the battle, Shinnosuke reveals that "Yoriko" is Reiko Nishihori, the daughter of Koya Nishihori, 005's host, whom Chase destroyed during his time as Protodrive with Shinnosuke at that same time arrested Koya for attempted robbery and murder. Reiko was never Ryo's sister, but she was one of his customers. Reiko's reason for committing such act is not to avenge her dad, but to make Go commit the greatest crime from her death (her true plan is to make the Kamen Rider (the face of justice) commit the most heinous crime by killing her). Go quickly compare his situation to Reiko in his mind, having their fathers turned them into what they become now.
At the hospital, Seeker's suspended animation effect on Genpachiro has worn off, with Rinna visits him and grew flirtatious after their earlier act as husband-wife pair in one of their undercovers. Meeting the Roidmudes Heart and Medic, they amaze 001 for handing over his power to Roidmude 050 (the ability to induce madness in a population) with 001 decides to make use of Go Shijima/Kamen Rider Mach as their ultimate weapon. At night, while Go is wandering around with suffering hallucinations of Shinnosuke, Kiriko and Banno, Brain appears out of nowhere and approaches him.
- Bad "Bad Acting": Shinnosuke's plan to get his suspended lifted involves staging a fake Roidmude attack on Nira. All of the players involved (everyone in Special Crimes plus Chase as the "evil" Roidmude) exhibit this trope in spades during the performance.
- Break the Cutie: As it turns out, every single evil thing done by Seeker Roidmude was to break Gou.
- Daddy's Little Villain: Seeker's human host, Yoriko, actual name is Reiko Nishihori, the daughter of the villain from Episode 0.
- Downer Ending: Hoooo, boy! All those people were harmed specifically to break Gou. The woman who asked him to help find her brother? She's Seeker Roidmude's human host, who got close to him just to infect him with the Hate Plague. The whole ordeal leaves him broken... and then Brain appears before him.
- Mood Whiplash: The episode goes from a wacky scene of the heroes putting on a terribly acted "play" to get Shinnosuke un-suspended, to a surprisingly dark Reveal of the true purpose of Seeker's attacks, culminating near the end with #001's ultimate plan - to use psychological warfare to manipulate the emotionally and mentally unstable Gou into fighting the other Kamen Riders.
- Secret-Keeper: Along with Mr. Belt, Shinnosuke must harbor the secret of Kiriko's relationship with Dr. Banno from said person.
- Shaking Her Hair Loose: Yoriko lets her hair down when she reveals herself to be Seeker's human host.
- Thanatos Gambit: "Yoriko" planned for Mach to kill her alongside the Roidmude, so that he would truly become beyond saving. Thankfully, Shinnosuke put an stop to it.
- Unspoken Plan Guarantee: The plan to lift Shinnosuke's suspension isn't revealed to the viewer before it put into motion. And it is glorious.
- The Roidmude Count: 60The Answer: To enrage Gou.
