The test for the Z Combination between Shinkalion Z N700S Nozomi and Zailiner HC85 Hida, which were built by Abuto according to his father's blueprints, has failed. Abuto, who has been rushing to catch up with his father, is taken by Shima to visit his father's former workplace, which is the "Railway Technical Research Institute," the leader and pioneer of railway technological innovation.
A Z Combination test is being run with the N700S and its Zailiner, the HC85 Hida. Unfortunately, something goes wrong and the combined Shinkalion is unable to move. As the mechanic, Abuto is the most concerned with this unexplained occurrence. Shin tries to calm him down afterwards by bringing Abuto a drink. The two sit outside and talk, Abuto mentioning how everything about the Zailiners and Z Combination came from the knowledge his father left him. The problem is, the HC85 is the first Zailiner to ever feature a double-carriage combination. Although it's supposed to supply the N700S with Ultra Evolution Current through a pre-installed Ultra Evolution Generator, the test showed that it was unable to withstand the sheer amount of power. Thus, it may have short-circuited, but this is still unclear. Abuto's idea to fix the issue is to get a cable that can convey the power without any loss. This would be never-before-developed technology. Shin likens this to OOPArts, which he explains to Abuto could have come from aliens. Abuto is skeptical, hearing another of Shin's stories, but Shin rationalizes that if the Z Codes were sent to Abuto's mind by his father, it's probably because his father was an alien. Abuto is not amused by this.
On the train ride back home, Abuto reflects on his dreams about his father, and notices sparkling in the sky. He's able to recall a childhood memory where he was walking with his father.
In school the next day, Abuto continues spacing out, thinking of his father, but is still able to answer a math question when asked. Hanabi comments that the power supply in Abuto's head never switches off, which reminds him to think about his search for a power supply for the HC85. He starts scouring through books after school, but finds nothing useful, and is frustrated that his father won't provide him with any answers this time. Shima comes to check in on him, and is surprised that there's a problem a genius like Abuto can't solve. Abuto argues that he isn't a genius, as he didn't just make up the blueprints from nothing. Shima argues that no one ever does that, likening it to the history of the Shinkansen, and how each model was based upon past technology. Shima adds that Abuto's father also said technology is meant to be passed down from generation to generation. Abuto admits that he feels he needs to resolve the issue with the HC85 to be his father's equal, which he needs to happen so they can meet again. Shima thinks that they can possibly meet. He tells Abuto they're going out the next day, and to bring Shin with him.
The place Shima wanted to take Shin and Abuto was the Railway Technical Research Institute. This place is significant because it was the predecessor of the Railway Technical Research Institute who originally designed the Shinkansen. It's the headquarters of railway technology. Shin is impressed because the technology looks very alien to him. Abuto asks Shima why they came, to which he replies Abuto has an appointment there. He's going to learn what Tokonami was researching there.
A researcher shows Abuto a superconducting feeder cable. This is technology which can be used to send electrical currents to the overhead lines of a railway with nearly zero transmission loss. The cable had been named an "Ultra Evolution Conductivity Cable" by Tokonami, as it was designed exclusively for use with Ultra Evolution Current. Although development was stopped it still reached the point where it could be used. Upon touching the cable, Abuto gets flashes of memories of the time his father was constructing it. Shin thinks the cables are inhabited by spirits, and is surprised when Abuto doesn't object to his guess. Abuto mentions that Shima was there too when it was built, having seen him in the flashes. Shima explains that he was working under Tokonami as a maintenance engineer, and that Tokonami always gave him absurd requests.
Regardless, Abuto thinks the cable may be the solution he was looking for, and asks Shima, who says that Abuto is too much like his father. Abuto asks him to install the cable in the HC85, which again reminds Shima of Tokonami and his requests. He agrees though, as long as Abuto and Shin help out.
Meanwhile, a Giant Monstrous Being is detected, which Ryūji identifies as Overlord Nobunaga. There are numerous enemy signals appearing near Sekigahara. A Capture Field with maximum diameter is launched over the area. Help is also requested from Ōmiya Branch, so Hanabi and Taiju launch while the E5 is put on standby at Tokyo Station. Shin asks if he can wait and help Abuto with the cable, but Abuto tells Shin to go. Shin points out that it would be better if Abuto rode there with him on the E5 with the completed cable, which Abuto agrees to.
Nagara also launches in the N700S. Once he transforms, he's immediately bombarded with hundreds of arrows from the sky. Seeing the soldiers who attacked, Nagara is excited to be in what appears to be the Warring States Period. Despite his brother's instructions, Nagara rushes in and starts attacking recklessly, though he is doing a good job.
Taiju and Hanabi arrive then to help. By then, Abuto has finished with the cable, and is already being driven to Tokyo Station by Shima. As planned, Shin then drops off Abuto and the cable with the E5 in Nagoya Branch's hanger, where the HC85 is already standing by.
Both Taiju and Hanabi's weapons have run out of power, and the soldiers are closing in on Nagara. Shin then appears in the transformed E5 to help, and tells Nagara that the HC85 is coming as well. Nagara combines the N700S with it, and this time is able to move. Nagara makes short work of the remaining enemies with his Hida Hybrid Naginata.
After the battle, Abuto notices The Dark Shinkansen once again. He heads after it, thinking that if he had the most advanced technology and knowledge he could have completed the cable on his own. With the belief that he'll be able to learn more and finally meet his father, Abuto boards the train. Shin calls, asking where Abuto is, and he gives the cryptic reply that he has a clue to where his father is and is going to meet him. Abuto assures Shin he'll be right back. As he heads into the cockpit, his Z Gear becomes capable of activating the shinkansen, which the announcer's voice calls the Dark Shinkalion.
In the episode
- Shinkalion Z N700S Hida makes its debut.
- The Dark Shinkansen makes its physical debut after its brief appearances in the past episodes during Abuto Usui's dreams.
- This is the first episode to feature Running Up Voltage as the ending theme.
- The opening theme played again as an insert song during Shinkalion Z N700S Hida's battle.
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
- Nagara Anjō- Nao Tōyama
- Shimakaze Anjō- Yūma Uchida
- Goichi Shima- Takahiro Fujiwara
- Sougyoku- Kenji Yamauchi
- Ryūji Kiyosu- Ryota Osaka
- Rindo Hashima- Takanori Hoshino
- Kasumi Abiko- Sayaka Senbongi
- Suruga Hamamatsu- Ryota Iwasaki
- Researcher A- Shogo Sakata
- Teacher- Naomi Maruyama
- Z Gear Announcements- Bonji Jinbo
- Script- Kenichi Yamashita
- Storyboard- Masato Sato, Koichi Ohata
- Episode Director- Sumiko Sasaki
- CG Episode Director- Koichi Ohata
- Animation Director- Shunsuke Igarashi, Shin'ichi Suzuki