Dark Side(ダーク サイド, Dāku Saido) is the first Ultraseven 35th Anniversary: EVOLUTION episode of Heisei Ultraseven. Although the first, it was released after the fourth episode, "Innocent".
Five years after Seven left Earth, a peaceful era continued thanks to the Earth Non-Interference Treaty sent from space, and TDF was also heading towards downsizing. Kazamori resigned from UG, and Satomi was on leave from her duties as a reserve member. At that time, a new member named Yuki joined UG. Yuki and Rumi immediately headed for the investigation of gravitational anomalies, but Rumi was suddenly captured by the Alien Pegassa and taken into the Dark Zone!
Plot[]
Five years had passed since the Omega Files incident. Kazamori had since retired from being an Ultra Guard member and visited Satomi at her holiday villa. He admitted that he had no knowledge of what happened when Seven masqueraded as the former and is currently feeling a sense of loss with the Ultra's departure from Earth. For his crimes in interfering with the human-Nonmalt war, Seven was sealed at the Horse Head Nebula by the entire universe itself.
At some point during Seven's departure, mankind received a peace treaty from the entire universe, giving assurance that Earth will not be invaded while TDF prepared for their arms reduction and Ultra Guard to be disbanded. UG was introduced to a new team member named Yuki Kisaragi, who was previously a member of the special force. Alongside Rumi, Yuki was sent to investigate a gravity anomaly in a particular location and discover an Alien Pegassa. Despite the alien's non-aggression approach, Yuki's hasty firing caused the former to retaliate by sending Rumi to the Dark Zone. Back in her early days as a special force officer, Yuki was rendered unconscious after an alien attack, causing her to attack any of them on the spot due to the aforementioned trauma. Unaware to the UG officers, she constantly reported her actions to TDF staff officer Inagaki. Mizuno discovered a strange device made from the same metal from Pegassa City and finally connected the dots that Alien Pegassa was the perpetrator.
Yuki paid her visit to the orphanage she was raised in (which happened to be in the same vicinity in the crime scene) and told her caretaker, Sayuri, to take the children away for safety. Shiragane discussed this matter with TDF officers Saijou and Inagaki, the latter decided to keep the Pegassa's case a secret from the civilians. As Saijou's men drove Shima and Yuki away from the crime scene, Satomi returned to her duty as a UG officer. Meanwhile, a pair (Tashiro and his junior) of TDF researchers discovered muons coming from outer space.
Satomi and Yuki lured Saijou's men away from the crime scene through a diversion. The Dark Zone reappeared to drag Satomi into it, while Yuki was injured and forced to flee from the scene through Kazamori's arrival. A lone Pegassa revealed that his action was done so as to avenge those who were killed in Pegassa City by taking Earth as their replacement home. After discovering that Kazamori had no idea as to why the alien would go as far as to reveal his motive, the alien quickly realized too late that the young man was not Seven and was quickly killed by Saijou. Kazamori advised Saijou not to trust other members in TDF, especially since his own men were killed and replaced with impostors.
Kazamori met Sayuri while tending Yuki's injury, having been summoned to the orphanage via telepathy. Meanwhile, Satomi reunited with Rumi in the Dark Zone to discover the a rather peaceful Alien Pegassa explaining what happened in the incident; after the destruction of Pegassa City, the surviving members split into two factions, the radical group who sought to overthrow mankind for the ownership of Planet Earth and the moderate faction who lived peacefully with the human society. This benevolent Pegassa had a leader (Sayuri) who ran an orphanage to take care of children who suffered the same misfortune as they did. The radical faction had been preparing their invasion for years to weaponize the Dark Zone into devouring an entire city block into an alternate dimension. Sayuri confessed to Satomi that after being force to abandon her own children in Pegassa City, she founded the orphanage to atone for her mistake. Yuki was one of those children she cared for after the latter was tormented by her abusive parents, going as far as to join TDF to protect the orphanage in return. Discovering her caretaker as an alien, Yuki became hesitant to kill her due to the times the spent together.
Kazamori slipped into the Ultra Guard headquarters to steal the device for Sayuri, arriving on time to prevent her (as well as Satomi and Yuki's) assassination from a radical Pegassa member. The device was one of the component of a device used to destroy the weaponized Dark Zone, as it was hunted down by the radical Pegassa faction and a few of the moderate Pegassa even sacrificed themselves to protect it. When the Dark Zone started to appear, Saijou can only hope for Ultra Guard's assistance. Sayuri choose to sacrifice herself by entering the Dark Zone and activated the neutralization device at the cost of her own life. In her final moments, she revealed to Kazamori that the answer to his problems lies in the currently imprisoned Ultraseven. After Sayuri's death, a strange saucer-like creature appeared in the sky.
Yuki decided to abandon her contact with Inagaki, while the source of the muon was traced to the same location where Seven was imprisoned.
Each episode was originally released on a separate DVD. The complete series was later released in a DVD box set titled Ultraseven 1994～2002 Perfect Collection on April 18, 2012.[1][2]
It brings back Alien Pegassa after 35 years since the original appearance. Designer Akihiko Iguchi updated the suit, changing it from two pieces to a single-piece design and adjusting colors to fit modern visuals.[5]
Hiroko Sakurai guest stars as Teacher Sayuri, her third role in the Ultraseven series. She previously appeared as Sanae Yamabe (episode 12) and herself in Ultraseven - Operation: Solar Energy.
Sakurai joined at producer Masahiro Tsuburaya's invitation. She aimed to portray Sayuri with gentle kindness, highlighting the tension between her and Alien Pegassa during their dialogue.[6][7]
The hardest part came on the last day, when she had to quickly learn a revised long dialogue. Though she memorized it fast, she sometimes confused old and new lines during filming. The director requested a long take, so Sakurai worked hard to adjust.
His role was to continue the story of the missing Ultraseven from the previous series finale in a five-episode arc. By the time he joined, the main plot and direction were set, so he focused on keeping the story consistent. Since the series released monthly rather than weekly, maintaining each episode's quality was important.
For this episode, Ohara mainly rewatched the original series' "Dark Zone" and works by director Kazuho Mitsuta for reference.
Within the story framework, Ohara had freedom to add his creative touch. He consulted frequently with producer Masahiro Tsuburaya and agreed to keep the core story intact while expressing his vision.
This episode shares similarities with Ohara's earlier work on Ultraman Neos episode 7, "King of the Biosphere," especially the symbolic use of a music box. Ohara said the music box became an accidental motif in his works, but here it carries most of the episode's emotional weight, so he ensured it felt natural in the story.
Though the script didn't explicitly mention the "Dark Zone" or "Hide-and-Seek," Ohara added these elements to deepen the narrative. He used the music box as a trigger for Yuki's involvement and Sayuri's fate, connecting it with a hide-and-seek game to strengthen emotional impact.
Since the episode targeted a more mature audience, Ohara took a serious tone in performances. He included a childhood scene where Yuki sees Sayuri emerge from the school's "Dark Zone" while playing hide-and-seek. Yuki forgets this memory until after Sayuri's death. Ohara worried viewers might misinterpret this as Sayuri always hiding there during the game.
Ohara also discussed Mika Katsumura's role as Yuki. He was responsible for shaping her character and rejected Katsumura's idea to make Yuki cold and detached like Nikita. Instead, he wanted Yuki to show emotional depth. For the scene where Sayuri dies, Ohara asked Katsumura to deliver a powerful, sorrowful crying performance.
