During a career counseling meeting, Yukina Shirahane learns that she is currently failing at Tateyama International High School, although determined to visit Mars someday. After school, Yukina and Mika Ogino go to the United Nations Kurobe Laboratory, a research facility where their parents work. Meanwhile, the Ministry of Defense detects a meteorite heading for Japan that divides between Toyama and Nagano as it enters the atmosphere. Minoru Aramata shows Yukina a large black cube and a gigantic geoframe found while excavating for the Kurobe Dam sixty years ago. Suddenly, one of the meteorite fragments crashes near the United Nations Kurobe Laboratory. A huge rose-colored geoframe called the Headless and small geoframes called Cactuses appear. The research facility dispatches shield-like geoframes called Dwarves to battle the Cactuses, while director Hiromi Shirahane authorizes pilot Tom Borden and navigator Liu Shenmei in the GAUS 1 to fight the Headless. Yukina opens the Cube after touching a glowing red panel, revealing Kennosuke Tokisada Ouma, a naked man who kneels and calls her princess. He relentlessly defeats one of the Cactuses that enters the building, while Tom and Shenmei manage to defeat the Headless outside. Kennosuke is then subdued by six security guards.

In the past, Princess Yukihime inquires about people who live in foreign lands beyond the sea. In the present, a huge geoframe called the Yellow Crab lands on the coast and heads towards the shore accompanied by many Cactuses. Major Arthur Graham detects the landing of more hostile geoframes in other countries worldwide. Hiromi goes with Dr. Jules Hausen to interrogate Kennosuke, but Kennosuke manages to escape and take Yukina, who he soon realizes is not the princess. He calls upon the Cube, which transports them to the underground storage keeping the gigantic geoframe called the Black Relic. The Cube docks with the Black Relic, which Kennosuke activates as the pilot and uses to smash out of the facility with Yukina onboard as the navigator. The defense forces attack the Yellow Crab with little effect, while Hiromi orders the defense forces not to attack the Black Relic. Kennosuke and Yukina attack the Yellow Crab, but they become surrounded by four sword-wielding geoframes called Ogres. After Kennosuke and Yukina defeat the Ogres, they prepare to destroy the Yellow Crab, but a tractor beam in the sky takes it up to an alien mothership instead.

Sixty years ago, the Cube and the Black Relic were discovered near the Kurobe Dam, where the United Nations built a large research facility to study them. In the present, Graham and Rita Ferreira Mendes confirm that the Cactuses are unmanned. Kennosuke and Yukina travel outside the currently uninhabited Toyama Castle, but Kennosuke fails to adjust to modern fashion and technology. Despite the Black Relic immobilized and Kennosuke being captured by the United Nations forces, he escapes custody again until Sophie Noël tackles him before two security guards activate a shock collar around his neck. Oshō Yakushi talks to Kennosuke, learning that he was just a soldier assigned to fight against the mythical invaders called Ogres. Kennosuke later uses a diversion by Koharu Shirahane to escape yet again and take her to the mountains. However, a Cactus appears and abducts Koharu. Kennosuke returns to the research facility and calls upon the Cube, taking Yukina onboard as they pursue. Although Kennosuke's sword breaks during the battle, Tom and Shenmei fortunately arrive to destroy the Cactus and rescue Koharu. Kennosuke finally accepts that he is now in the future upon seeing a cliff split in half during a battle in the past.

Kennosuke has dinner with Yukina, Koharu and Yakushi, trying modern rice and curry for the first time. The Ministry of Defense analyzes that six giant geoframes have landed across the world, but only Japan was able to defeat one. The geoframes appear to be searching for something rather than attacking. Kennosuke watches a historical movie about the Battle of Okehazama on television, then chases Yukina's pet ferret Kojo riding on a robotic vacuum cleaner. After taking a bath, he struggles to put on boxer shorts, so he ties on Yukina's favorite towel under his robe instead. Later, Yukina takes Kennosuke to the Tateyama Mall, where he marvels at the strange new world. They encounter two reporters who remember that Yukina's father Takehito Shirahane advocated a bizarre theory before his disappearance about the legend of Ogres in association with aliens. After evading the reporters and returning home, Yukina shows Kennosuke a notebook written by Takehito about the Ogres, including a passage on the extermination of the Washiba Clan by a mysterious unknown power. The notebook also contains a candid blurred image that Kennosuke recognizes as the Ogre that attack him and Yukihime 450 years ago.

Yukina goes to school, only to be horrified when Kennosuke has been enrolled as a student. Forty hours ago, Kennosuke and Yukina were stationed by the United Nations Kurobe Laboratory, where they are the only ones who can operate the Black Relic since it implanted them with nano-machine channels. Kennosuke painted a rough sketch of an Ogre that the United Nations can use for identification. Graham introduced Kennosuke and Yukina to Tom, Shenmei, Sophie and Toshiyuki "Sebastian" Mozumi, otherwise known as the GAUS crew. In the present, Kennosuke struggles with modern school life. After school nurse and student counselor Marina Unami directs Kennosuke to the library, he learns that the era of the samurai has long passed. Sophie then questions Kennosuke and Yukina for their reason for fighting, but she leaves in disappointment when Kennosuke desires revenge and Yukina has uncertainty. While Paula Kowalczyk and Girolamo "Giro" Casiraghi transport the Black Relic to Tateyama, North American Aerospace Defense Command (NORAD) detects another object launched from the alien mothership heading for Toyama. As three hostile geoframes land near the town, the GAUS crew prepare to be mobilized while Kennosuke and Yukina reach the Black Relic in the impending battle.

While inside the Black Relic at the Toyama Kitokito Airport, Kennosuke and Yukina duel against the Yellow Crab, but the two Headlesses attack the Black Relic from behind. Meanwhile, Jundai Kayahara and Ryoto Akagi leave the school to approach the battle site as the citizens are evacuating. The GAUS crew deploy their units and arrive to engage the Headlesses, managing to destroy them. Kennosuke and Yukina struggle to defeat the Yellow Crab due to its high-output gravity shield, but they finally manage to destroy it. During the battle, Jundai and Ryoto commence live streaming from a mobile phone which is viewed worldwide. A pilot encased in armor emerges from the wreckage of the Yellow Crab and removes his helmet, surprisingly having a human appearance. He announces himself as Hedo, a border reform officer for the extraterrestrial organization Efi Dorg. Then, Hedo asks Kennosuke, wielder of the large humanoid geoframe Grongol, why he betrayed Efi Dorg. Lastly, Hedo detonates the Yellow Crab with him inside, causing a devastating explosion.

Following Hedo's suicidal death in the Yellow Crab, the United Nations Kurobe Laboratory assesses that the geoframes that landed in various parts of the world are confirmed to be related to the Black Relic of 450 years ago. Kennosuke mentions that the Black Relic was stolen by Yukihime, and he still seeks revenge for the destruction of the Washiba Clan. However, Yukina refuses to be further involved in anymore violence. While on the way to school, Kennosuke and Yukina learn from José Carlos Takasuka that Jundai and Ryoto have gone missing. Sophie later presents Yukina with an ultimatum to either die fighting or die trying to escape the fight. Kennosuke has conflicted thoughts about Yukina riding behind him in the Black Relic, since he needs her to exact his revenge. Yukina realizes that Kennosuke has this selfish desire of revenge that would ultimately lead to his death. On the Efi Dorg Spaceship, the Gezon-Reco Company, people dressed in battle armor, discuss their strategy of gathering pieces of the legendary Pivot Stone. They send Earth a demanding message for the return of the Black Relic. After having an argument with Hiromi, Yukina leaves the house the next morning.

Paula and Giro discover that the Black Relic can absorb nearby mass in order to repair itself. As Hiromi and Graham decide that it is best not to hand over the Black Relic to Efi Dorg, Hiromi receives a call from Koharu that Yukina is gone. It turns out that Yukina is secretly sulking at Mika's house. Kennosuke, Koharu and Yakushi eat some leftover gyōza, but Yukina later returns home and finds it empty, deciding to leave somewhere. Meanwhile, Jundai and Ryoto return to school unharmed, but they are scolded by Naoki Takekuma for live streaming the battle at the airport. Elizabeth "Beth" Butler informs Graham that a geoframe called the Longarm was discovered in North America and has returned to the Efi Dorg Spaceship with an unknown object. After returning home from school, Kennosuke overhears from Yakushi's phone call that Yukina went to Kurowashi Valley, and he goes after her on horseback. While Yukina is searching for the Washiba Clan's castle, she is attacked by a Cactus. A small blue geoframe called the Liddy stops and destroys the Cactus, while Yukina falls unconscious. With no reply from Earth, Efi Dorg officer Fusunani is dispatched to Earth's surface.

The Longarm and four Headlesses advance towards the Kurobe Dam. The GAUS crew are on standby, while Hiromi continues to worry about Yukina. Meanwhile, Yukina awakes inside a secret base full of old appliances, chancing upon a bloodstained notebook written by Takehito about the destruction of the Washiba Clan. She faints after seeing the Liddy once again. Jundai and Ryoto later find Yukina at a bus stop shelter, but Kennosuke also arrives at the scene. Instead, Yukina agrees to ride with him in the Black Relic, as long as he does not go off and die. After being retrieved by the defense forces, Kennosuke and Yukina deploy in the Black Relic and attack the Longarm and the four Headlesses. However, they are surrounded and caught in a tractor beam that starts to pull them towards the Efi Dorg Spaceship. The defense forces fire missiles at the hostile geoframes, which enables the Black Relic to break free. The GAUS crew arrive and defeat the Headlesses, while Kennosuke and Yukina fight and defeat the Longarm. Fusunani emerges from the Longarm and surrenders.

Aramata, Paula and Giro examine Fusunani's sword, while Hiromi and Hausen scan Fusunani's body, finding out that both are similar to those of Kennosuke. Fusunani tells Carrie Dunham and Heath Kingsley, specialists from the extraterrestrial research division, that he is a border reform officer affiliated with Efi Dorg's Gezon-Reco Company. After Takekuma crushes Ryoto's dreams of being a potential GAUS pilot someday, Ryoto goes to the arcade to score high on a first-person shooter. When he leaves, Jundai and Carlos witness Sophie scoring extremely higher. Fusunani says that the aim of the Gezon-Reco Company is to bring prosperity to savage planets. The objects they seek are fragments of the Pivot Stone that was broken when an advance team was wiped out 450 years ago by the Black Relic, whose wielder seemingly betrayed them. Dunham and Kingsley question Kennosuke about what happened 450 years ago, but he mentions that the Ogres destroyed the Washiba Clan's castle and he then fought alongside Yukihime in the Black Relic before her inevitable death. He denies being part of the Efi Dorg's advance team, but Dunham and Kingsley remain suspicious. Meanwhile, Fusunani escapes from the security guards and remotely summons the Longarm.

The Longarm makes its way towards the United Nations Kurobe Laboratory and pierces a main power line with its sword. The GAUS crew deploy and intercept the Longarm outside. Meanwhile, Fusunani kidnaps Yukina and follows her to the excavation site, where he recognizes a Pivot Stone fragment. After they head to the deployment bridge near the Black Relic, Kennosuke confronts Fusunani in battle. Kennosuke accuses Fusunani of being Sadakuro Saito of the Washiba Clan, but Fusunani accuses Kennosuke of being a traitor and having his memories altered. As Kennosuke stabs Fusunani in the chest, Fusunani falls to his death, which then causes the Longarm to collapse. Dunham and Kingsley cannot discern whether Kennosuke or Fusunani was telling the truth of their past. After Ryoto realized that he was beaten by Sophie in the arcade, he fails to overtake her score after numerous efforts. In order to prevent Kennosuke from sitting like a statue all day, Yukina invites him to hike with her to the secret base where she saw her father's notebook, but all they find is a giant crater. While eating onigiri together, Kennosuke reaffirms his promise to always protect Yukina.

On the Efi Dorg Spaceship, the Gezon-Reco Company retrieves another Pivot Stone fragment from Earth, but they are frustrated at their slow progress of collecting all the fragments, plus they have yet to locate the important Key Stone. At the end of class, Mika notices that Kennosuke is doing better at English literature than Yukina. During a summer training camp, the GAUS crew put Kennosuke, Yukina and Ryoto through a series of rigorous physical training. However, Yukina and Ryoto struggle to keep up the pace, and Ryoto himself is forced to withdraw after injuring his leg. After Kennosuke and Yukina undergo intense educational studies in the classroom, they train in the shooting range, though Kennosuke uses a sword as a substitute. They even simulate mountain hiking while in a swimming pool, but a shocking accident leaves Kennosuke and Yukina to take a break. In the meantime, the United Nations Kurobe Laboratory experiments with gravity control for Tom and Shenmei in the GAUS 1 to walk on water with limited success. By the end of summer training camp, Yukina eventually improves her fitness. Kennosuke is given back his sword and is unshackled from his shock collar.

The Black Relic and the two GAUS units fight to drive a geoframe called the Spider controlled by Efi Dorg officer Mirasa from the urban area. The Spider is stabbed during battle, being forced to retreat and recover. Yukina's class plans for the school's cultural festival and decides on the theme "Teach me about Efi Dorg" since there are three geoframe pilots in the class. The other students build a large replica of the Black Relic through the night, while Kennosuke and Yukina bring food for them on the Cube, which is airlifted back to the research facility by a helicopter of the defense forces. On the day of the cultural festival, Mika encourages Kennosuke and Yukina to try out cosplay, but the two go on to enjoy the various exhibits instead. Efi Dorg officer Muetta attends the cultural festival cosplay competition in her battle armor, which is mistaken for a costume. While a forum for Kennosuke, Yukina and Sophie as geoframe pilots is in progress, Muetta suddenly appears on stage and stabs Kennosuke in the chest with her sword. Kennosuke is stunned to see that Muetta's face looks just like Yukihime.

Before Muetta can kill the badly wounded Kennosuke, she is stopped by a masked and cloaked Demon. In the meantime, Takekuma treats the wounds of Kennosuke. Muetta evades the attack by the Demon and calls for her geoframe called the Medusa, which launches from the Efi Dorg Spaceship. Once inside the Medusa, she is immediately attacked by the GAUS crew in their units, but she manages to escape. Back at the United Nations Kurobe Laboratory, Graham briefs Kennosuke and Yukina on the current situation. Kennosuke recovers enough to pilot the Black Relic, with Yukina reluctantly behind as the navigator. Kennosuke and Yukina confront Muetta in the Medusa, who Kennosuke still believes is Yukihime. Then, Mirasa in the Spider arrives to join the fight, but seems to be uncoordinated with Muetta. However, the GAUS crew arrive as well and engage in battle against Mirasa. The Black Relic and the GAUS units fight as a team and damage the Spider, prompting Muetta and Mirasa to retreat back to the Efi Dorg Spaceship.

Kennosuke is taken back to the United Nations Kurobe Laboratory for medical treatment following the battle against Muetta and Mirasa. Sophie and Sebastian realize that the residents are evacuating the area due to the recent geoframe attacks. Carlos has to face moving from Tateyama to Madrid. At school, the students show concern to Yukina about Kennosuke's condition. Meanwhile, Kennosuke has a past vision of Yukihime and the Demon conferring about him when he survived. Hausen is impressed to see that Kennosuke has recovered from his near fatal wounds through tissue regeneration. Mika invites Jundai, Carlos and Ryoto to film a cosplay fan video for her. Graham informs the GAUS crew that he will prepare single-seater GAUS units, meaning that Shenmei and Sebastian are no longer navigators. Sophie received a call from her father and will be returning to France. After Sophie pays for Kennosuke's meal, Kennosuke convinces her to go against her father's wishes of returning to France. On the Efi Dorg Spaceship, the Gezon-Reco Company debate their next course of action, but Muetta and Mirasa seek to redeem themselves and secretly dispatch to Earth.

Muetta and Mirasa arrive at Kurobe Dam using atmospheric entry suits. Yukina, Mika, Jundai, Carlos and Ryoto travel to search for a location to film Mika's cosplay fan video. Mika has also invited Marina along to lift her spirits after she tenders her resignation due to Muetta's attack at the school's cultural festival. Graham begins trial simulations on single-seater GAUS units to increase their capacity to deal with enemy geoframes, with mixed success for each member of the GAUS crew. With Sophie departing for France soon, Kennosuke has a conversation with her about freedom and loyalty. Muetta and Mirasa gain entry inside the United Nations Kurobe Laboratory and disguise themselves as miners. They capture Kennosuke, who still believes that Muetta is Yukihime, but Muetta denies knowing him. They find the excavation site with the final fragments of the Pivot Stone. Confronted by the defense forces, Kennosuke tries to defend Muetta. However, Sophie says that he is foolish, and she vows to stay at the research facility. As they are about to leave, Mirasa stabs Muetta so that she can take sole credit for the discovery. Muetta jumps from the dam wall into the rushing waters below.

The Gezon-Reco Company notices that Efi Dorg officer Imusa has descended again to Earth in order to find the three remaining Pivot Stones including the Key Stone. After viewing footage of Mirasa stabbing Muetta at the Kurobe Dam, Kennosuke storms out and Yukina follows him. Hiromi waits for replacement parts to arrive for the GAUS units. Kennosuke, Yukina and the GAUS crew debate whether or not Muetta is really Yukihime. Afterwards, Kennosuke and Yukina deploy the Black Relic to search for Muetta in the river. However, Efi Dorg officer Yoruba arrives in a flying geoframe called the Bluebird to check on his comrades, also shooting down a cargo aircraft carrying the replacement parts. The cargo aircraft crew manage to offload the replacement parts before crash-landing, where Kennosuke and Yukina saves the crew from crashing into the research facility. Yoruba finds Mirasa, who lies that Muetta has already died, but he goes to find Muetta. He attacks the Black Relic in the air, but the Demon attaches a winged geoframe called the Crow to the Black Relic to help Kennosuke and Yukina. Because of Kennosuke's mistrust of Ogres, the Demon departs but promises to assist him if needed.

After Hiromi tells Kennosuke and Yukina that the defense forces are searching for Muetta, Hiromi gives Kennosuke and Yukina a three-month salary. While Kennosuke pays for dinner at home, Yukina later invites Mika, who then invites all their classmates, to Toyama Memorial cottage in order to visit "Kenshin's hidden hot springs" for the weekend. However, only the core group of Yukina's friends and family end up going. After everyone enjoys a meal cooked by Kennosuke, they then criticize the cosplay fan video edited by Carlos, which blasts heavy metal filmed in a black and white format. They come up with better ideas for a new film with sports, drama, romance, horror and ghost adventures as the theme. The next day, the wounded Muetta takes refuge at the hot spring, hoping to aid her recovery. After getting lost, Kennosuke and Yukina arrive at the same hot spring. They stumble upon Muetta, and the defense forces take her into custody. Just then, a Cactus appears, captures Yukina and escapes back into orbit.

The Cactus returns to the Efi Dorg Spaceship carrying Yukina in a bio-conveyance capsule, and the Gezon-Reco Company believe that Yukina is Muetta. At the United Nations Kurobe Laboratory, Hausen concludes that Yukina and Muetta share the same mitochondrial DNA, and Yukina was therefore abducted by mistake. Graham relieves Sophie of her duties. Later on, Sophie sees some writing appear on the ground outside the research facility, asking if she wants to learn the truth about Ogres. Hausen informs Hiromi that only Kennosuke's blood sample will be able to heal Muetta. When Sophie returns to her house, the Demon is waiting for her and introduces himself as Zelleager "Zell" Myundef Vishrai. As he explains that he is neither an Ogre nor an Earthling, he confirms that he is an enemy of Efi Dorg. Kennosuke begs Muetta to navigate the Black Relic to the Efi Dorg Spaceship with him as the pilot, to which she agrees but cannot guarantee his return. As they prepare to leave in the Black Relic, they see a recorded message from Yukihime imploring her ancestors to fight the Ogres and protect the Washiba Clan. Muetta then wonders more about her unknown past.

After escaping captivity, Yukina realizes that she is inside the Efi Dorg Spaceship, but she encounters Mirasa, who believes that Yukina is Muetta. After evading Mirasa, Yukina manages to access Efi Dorg's virtual database and learns about their plans of assembling the Pivot Stone. Yukina is further shocked to discover a head that resembles Yukihime. Meanwhile, Kennosuke and Muetta leave the research facility in the Black Relic, while Graham confines Hiromi for security lapse. At Sophie's house, Zell reveals to Sophie that Efi Dorg aims for planet domination, and he wants to avenge his compatriots slaughtered on his conquered planet. Before Sebastian charges inside, Zell leaves Sophie with a flash drive. Muetta requests retrieval to the Efi Dorg Spaceship and reports to the Grezon-Reco Company, learning that they planted seeds of life on various planets. When Kennosuke is detected onboard, Muetta is accused of being a traitor. Kennosuke and Muetta reunite with Yukina, leaving the Efi Dorg Spaceship in their geoframes, but are pulled away from orbit. Zell in the Crow intercepts and safely carries the Black Relic and the Medusa to Earth. The research facility receives a message that the Efi Dorg Spaceship is descending towards the planet's surface.

The Black Relic and the Medusa return to Earth assisted by Zell, but Muetta is consequently arrested. Zell states that Yukihime died 450 years ago and Muetta is a replica based on her genetic information. He further explains that Efi Dorg creates clones of the lifeforms that they conquer and embeds false memories in them to be loyal vanguards. He also tells Yukina that her father Takehito was a close friend. While citizens are evacuating, the Efi Dorg Spaceship launches multiple geoframes, including the Rockhead, the Bluebird and the Spider. Zell attaches the Crow to the Black Relic so Kennosuke and Yukina can confront Yoruba. Tom, Shenmei and Sebastian engage Imusa, Mirasa and the Headlesses on the ground using single-seater GAUS units. As the battle grows fierce and the research facility soon breached by the Headlesses, the Efi Dorg Spaceship drops many Cactuses, which release electronic parasites that take control of some of the staff. Sophie gets her friends to rescue Muetta from an overturned van, while Sebastian sacrifices himself in an attempt to destroy the Spider. Kennosuke and Yukina in the Black Relic pick up Tom in his GAUS 1, and they depart from the overrun research facility.

Kennosuke, Yukina, as well as the close-knit students and the remaining staff who evacuated from the research facility, retreat to the high school, which has become the new base of operations. The entire region is completely isolated from the rest of the world because of the barrier created by Efi Dorg. When Kennosuke, Yukina and Muetta stop by Yakushi's home to visit Hiromi and Koharu, Zell appears and explains how he met and befriended Takehito many years ago, shortly before Takehito died from a sudden avalanche. Meanwhile, Efi Dorg manages to excavate the Pivot Stone from Kurobe Dam's underground excavation site, using the mind-controlled staff as slaves. The Pivot Stone draws in surrounding heat, icing the area and provoking a snowstorm over Kurobe Dam. Muetta, having finally accepted the fact that she is a replica with false memories, escapes from the base of operations. Yukina collapses in the snow while searching for Muetta. However, Muetta finds Yukina, taking refuge in a cabin. Before Kennosuke reaches them, Muetta reveals that Efi Dorg plans to use the Pivot Stone to create a wormhole between Earth and its homeland, enabling a correctional fleet to storm the planet and subjugate it.

In the classroom, Jundai, Carlos and Ryoto argue over the fate of the world. In the base of operations, Zell and the research facility staff consider their limited options concerning the Pivot Stone while the barrier is intact. As Kennosuke, Yukina and Muetta joins the classroom, Sophie and Mika greet Muetta, who then explains about the correctional fleet soon storming through a wormhole. Takekuma enters the classroom and tells a story about two frogs jumping into a fresh pot of milk, one who drowned in it and one who churned it into butter to jump out. Later on, Takekuma has a career counseling meeting with Kennosuke, giving him insight on his future plans. After Muetta tastes modern cuisine for the first time, she receives advice from Marina about exploring her own identity. Carlos writes a movie script suggested during their hot springs adventure, titled "Demon Hell Brigade (Sturm und Drang)". Filming commences in the baseball field after the other students agree to participate in it. During the filming, Kennosuke asks Muetta to fight with him as an equal against Efi Dorg. Meanwhile, the Grezon-Reco Company extracts the completed Pivot Stone and ascends it above the Efi Dorg Spaceship.

Muetta decides to fight alongside the humans. While Graham asks Sophie to pilot the GAUS 1, Kennosuke and Yukina promise to protect each other. The Black Relic, the Medusa, the GAUS 1 and the Crow engage the Bluebird and the Spider. Meanwhile, Graham and Hiromi lead a small group of troops to recapture the United Nation Kurobe Laboratory from the Cactuses, managing to find the unconscious mind-controlled staff and reboot the control room. Sophie reunites with Sebastian, revealed to still be alive as he takes control of the GAUS 2. Kennosuke and Yukina defeat Yoruba, while Muetta defeats Mirasa. Lefil, leader of the Grezon-Reco Company, then descends and unites his geoframe with Imusa's Rockhead to create the giant geoframe called the Ogre. However, it is defeated executing Yukina's plan of using simultaneous attacks. Lefil returns to the Efi Dorg Spaceship, but ends up mortally wounded by Zell and revealed to be a clone from Zell's race. Zell uses a parasite to get Lefil to shut down the wormhole. The wounded Lefil reveals to Zell, Kennosuke, Muetta and Hiromi that Efi Dorg will send a larger correctional fleet that would reach Earth in 224 rotational periods.

Lefil says that Efi Dorg controls 85 percent of Zell's planet, which gives Zell hope that there may be a resistance movement. The Efi Dorg invasion force also had received communication that some planets subjugated by them are uniting. Muetta, confirmed to be an artificial creation, learns that all border reform officers are disposed of once their job is done. Graham fears that an arms race may start after the failed invasion, while Hausen and Dunham also fear that the immortal Efi Dorg clones like Kennosuke and Muetta may pose a threat to humanity. Zell tells Kennosuke, Yukina and Muetta about when he came to Earth with others of his race to find allies and fight Efi Dorg, but only found Kennosuke and Yukihime alive. The two were trained to control the captured Black Relic and defeated Efi Dorg, but only Kennosuke and Zell survived the battle. In the new climate of suspicion, Hausen has Muetta fitted with a shock collar and Kennosuke is treated as a threat. Kennosuke resolves to travel to Zell's planet with Zell and Muetta to fight Efi Dorg. After spending time in an amusement park, Kennosuke breaks off his engagement with Yukina, leaving her heartbroken.