Shin, who heard a rumor about a “mysterious giant” that appeared in the Railway Museum, Attempts an infiltration investigation with Hanabi, Taiju and Ayu. Then, they really find a figure that seems to be a giant. In order to befriend that giant, Shin involves Ayu and the others into a big search at the Railway Museum...?
Shin is enjoying a bowl of Sukiyaki with his family, disgusting Ayu by calling it "yokai sukiyaki", pointing out what yokai each ingredient looks like to him. Ayu does get revenge by stealing some of Shin's meat when he's not looking. Shin's mother asks about how things are going at the "Ultra Humanization Institute", still not realizing the true organization her son is a part of. Shin talks about all the friends he made, which reminds him of Abuto in particular, who left to find his dad. Ayu interrupts his worrying by asking Shin to accompany her to Saitama.
It turns out, Ayu takes Shin to an open radio studio, where Tatsunori Tsujimoto, a member of the band BOYS AND MEN, is being interviewed. Shin is surprised to see her there for Tsujimoto, but it turns out she's there for the radio's host, Bakabon Onizuka. Shin discovers that Abiko is also in the audience, and she's there to see Tsujimoto, though she denies it. To deter Shin's attention, Abiko reveals a news story about a mysterious giant who appeared at the Railway Museum. Shin is immediately excited to investigate, and Ayu follows after.
Shin, with Taiju, Hanabi and Ayu in tow, begins an investigation of the Railway Museum. He has them all dress in the getup of the Hiroshi Kawaguchi Expedition Series. Hanabi and Taiju are excited, but Ayu not-so-much. The team eventually comes across a figure who seems to be the giant. They pursue it, finding themselves in the archive room, where the giant is easier to see through glass. Taiju wonders if it plans to attack, but Shin warns not to show fear and declares his intent to befriend it. The giant having slipped away by the time the team gets behind the glass, Shin suggests that they split up and search. Ayu finds the giant, but is too afraid to strike it. She eventually throws down her net blindly, and ends up catching Sogō's head in it.
On the panorama deck, Shin again finds the giant. He calls Taiju and Hanabi over, and the three realize they now have it cornered in a place it can't escape. The giant turns to face them and is seemingly a steam train mascot character. Hanabi hits it with the hammer he'd been carrying, and the mask falls off. The three boys are terrified, but the mascot, actually the Kitoralsus Agent Genbu, simply asks if they're Shinkalion drivers. Minori appears then, complimenting Genbu for his good work. With his mask back on, he returns to entertaining kids as the museum mascot. After the kids leave, Genbu explains to Shin and the others about his past, and how he became friends with the previous Shinkalion drivers after they chose to coexist with the Kitoralsus rather than fight. Genbu also mentions that he knows about the fight against the Teoti, and Shinkalion Z.
Genbu offers to show the three drivers around the museum after they chat. Ayu finally finds the rest of the group then and is startled to see them with the giant. After being told that the giant was actually a costume character called "SL Grandpa", she gets annoyed and leaves.
Genbu then shows the drivers various areas of the museum. These include the Rolling Stock Station, the Job Station which has a driving simulator game they can play, the Science Station, and the Miniature Driving Train Park. The drivers want to use this as a chance to race each other, but it's impossible as they move slowly. The exhibit was built to learn safe operation of railways. Either way, they see it as a good opportunity to compete.
After driving, they return to the Rolling Stock Station to visit the museum's centerpiece, the Class C57 Locomotive. Having seen all the museum has to offer, Shin comments to Genbu how the railway is about more than just the drivers. That was also what Abuto showed him. Shin asks Genbu if there are any Abt System locomotives in the museum. There is one, which once ran from Yokokawa to Karuizawa. While talking about the train, Shin basically confesses that he's worries about Abuto, without saying as much. Genbu notices the important bond the two have. He tells Shin that they can overcome any challenge so long as they keep that bond.
Sougyoku, meanwhile, is meeting with the Teoti. He tells them that they must take action, and then the Shinkalions will appear. Then, they can crush the Shinkalions and the Ultra Evolution Institute. Valtom points out that Sougyoku already got in there once and failed. Sougyoku replies that they just need to cooperate this time. Neither Valtom nor Wadatsumi are happy with the idea, but Sougyoku replies that this is the will of Astrea, the third Teoti.
The three drivers are sitting with Genbu and having a snack while watching the Shinkansen pass by at the stallion. Genbu warns that while relaxing is nice, the battles are going to be more intense, so someone will have to take a role of leadership. Hanabi suggests Shin, and Taiju agrees to this. Genbu thinks that it's natural for the driver of the E5 to be the leader. He points out that the previous Shinkalion drivers were equal to him in strength, which was the reason they could have dialog with him. As Shin starts to ponder this, an unidentified Shinkansen is detected, and is on a course to Ōmiya. The group heads back to the base, Shin wondering if it's the "Dark Shinkansen" Abuto spoke of.
After a Capture Field is launched, Shin and the others transform their Shinkalions to take this new Shinkansen on. But it too transforms into a Shinkalion, fittingly named "Dark Shinkalion". Although the drivers are shocked by this turn of events, Shin is determined to beat it, even without Abuto being there. However, unbeknownst to him, Abuto is the one inside the Dark Shinkalion, and a voice is telling him to fight.
The drivers attempt to surround Dark Shinkalion and attack it from all sides. Taiju is taken down quickly, with Shin following. Hanabi tries to attack it, but is also defeated immediately. All three are struggling just to stand up. The Dark Shinkalion makes an attack from the air against the E5, but the attack is blocked by Genbu in his monsterized form. Genbu tells Shin to stand up and fight, while taking damage from the Dark Shinkalion's continuing attacks. It only comes to an end when Abuto is ordered to return by the voice. The Dark Shinkalion flies off on the back of a horse out of the capture field.
In the episode
- The Dark Shinkalion makes its physical debut after its brief appearance in the beginning of episode 8 during Abuto Usui's dreams.
- The Dark Horse makes its debut.
- Both Tatsunori Tsujimoto and Genbu make their return from the previous season.
Note: All characters are listed in order of their first appearances in the episode.
- Shin Arata- Minami Tsuda
- Abuto Usui- Akari Kitō
- Hanabi Ōmagari- Yuka Terasaki
- Taiju Togakushi- Michiko Kaiden
- Ayu Arata- Kanon Takao
- Toki Arata- Chiemi Ishimatsu
- Smat- Jun Fukuyama
- Genbu- J. Maxwell Powers
- Sougyoku- Kenji Yamauchi
- Valtom- Masaya Matsukaze
- Wadatsumi- Tooru Sakurai
- Kannagi- Yōhei Azakami
- Saijō Sogō- Kōsuke Gotō
- Kasumi Abiko- Sayaka Senbongi
- Misaki Ōishi- Satomi Moriya
- Minori Sanjo- Wakana Minami
- Z Gear Announcements- Bonji Jinbo
- Bakabon Onizuka- Bakabon Onizuka
- Tatsunori Tsujimoto- Tatsunori Tsujimoto
- Script- Daisuke Ishibashi
- Storyboard- Katsuhito Akiyama, Koichi Ohata
- Episode Director- Yoshito Hata
- CG Episode Director- Koichi Ohata
- Animation Director- Ippeita Watanabe, Tatsuya Yada, Yumi Takanashi, Motoki Hayakawa, Shigenori Taniguchi, Yosuke Fujino, Kazutaka Kawamoto