The Assault Team arrived to the coordinates point and realized that this time they face Gauna took the form of Shizuka's Garde, it makes them falter. Yuhata reminded that they are Gauna whatever its form. The three Gauna split, so does the assault team. Samari Squad face to G489, Nakazono Squad face to G450, and Kunato Squad face to G451.
Kunato Squad divide their respective duties, Honoka sisters duty to corner Gauna with Hyggs particel cannon firing, Nagate as support unit, and Norio as a lancer. When the first shot hit the G451, she gives voice response in pain, her voice is similar to that of Shizuka. Nagate immediately broke away from the formation and approached G451 although his squad-mates prevented. At the same time, entered the message from Extraterrestrial Research Division (ERD) requesting sample of the placenta for examination. Nagate using his Gatling gun, cut off the binding tentacles to object like "Shizuka", fired Hyggs Particel Cannon, and Norio send a deadly attack by Kabizashi, G451 defeated.
Extraterrestrial Research Division, asking placental samples to be inspected. Nagate then asked for permission to take a sample of the placenta-like Shizuka, and Captain Kobayashi allow it, while another Kunato Squad rendevous with Nakazono Squad.
Nakazono Squad engaged G490, the which communicates with them through radio with Shizuka's voice after killing each squad member of the Nakazono squad. Yuhata deducted, that G490 is the most powerful Gauna, as there is a pilot in it. In the end, Nakazono Squad annihilated by G490.
Samari squad engage and destroy G489, then rendevous with Kunato Squad. At the same time, Nagate has taken a sample of the placenta and rendevous with Kunato Squad.
Now, Kunato Squad try to engages G490. It's continues to communicate over the radio leading Kunato to panic and unable to fight. Honoka sisters were ordered to take over the operation and attack G450 after taking Nakazono Squad Kabizashi. As they both would launch attacks, G450 attacking Ho and as a result she is Killed in Action. G450 will attack Ren, but was stopped by the arrival of Nagate. While Samari Squad also joined, G450 chose to retreat. Because the energy of each unit is within a red border, Sidonia also retreat her assault team.
After the battle, the pilots mourn five of their companions who were KIA. At the same time, Sidonia issued a public statement regarding the previous battle, about Gauna shaped Garde attacking, they named Benisuzume or Crimson Hawk Moth. Placental samples taken by Tanikaze also reported as additional articles. Izana inquire about placenta samples in question, and Nagate give an answer, it is a perfect human replica of the Gauna's placenta who resembles Shizuka Hoshijiro. He also believes that one of the three Gauna were attacked before, there is a genuine Shizuka body.
Lala Hiyama came to Captain Quarter to inquire about Kobayashi decisions in the involvement of Nagate in each mission which she said was not fair. Kobayashi said, this is the Immortal Committe decision, because no one should be immortal other than them. Lala believes that the main purpose of the Immortal Committe give that sortie order is to kill Nagate. To convince Lala and herself, Kobayashi ensure that Nagate will not die in battle. In the middle of their conversation, enter a call from Professor Yure about the preparation of the "ritual" has been completed.
Lala returns to the dorms, without returning the greeting of Nagate and Izana, which causes them to think that Lala was sad.
Lala reminisces about the events of the "Fourth Gauna Defensive War" 100 years ago when almost all citizens of Sidonia perished during a Gauna invasion. Only 392 citizens and 25 council members survived Including herself, Kobayashi, Hiroki and Ochiai, who was held the responsible for the tragedy by discard all Kabizashi. But his life was spared from execution because several important files from Sidonia's archives were copied by Ochiai to his brain while deleting the original files. The files were then relocated to an auxiliary database accessible only through his brain which was transferred to a clone of Ochiai. The one who porpose the idea is Professor Yure Shinatose. After the incident, Hiroki disappeared without a trace.
80 years later, Hiroki reappearing as an old and aged man because he had renounced his immortality and refused to take life-prolonging medication. To preserve Saito's memory, skill and abillity, Kobayashi ordered the creation of a clone of Hiroki, to have his mind transferred to the child, which was in fact Nagate.
Hiroki holding Yure as captive, to show him where Nagate locate. Hiroki claiming that he will teach Nagate all of his pilot skills nonetheless, but Kobayashi rejected it, asked Hiroki to give up and return Nagate. Negotiations failed and Hiroki intend to kidnap Nagate. Kobayashi ordered the arrest on Hiroki, and fighting broke out. With the help of Lala, Hiroki managed to flee from the siege of security. Once again, Hiroki disappeared and not come back to the surface.
After the flashback, back at the dorms, Lala daydream while sweeping. Nagate call "Lala" as suggested by Izana to comfort her, but Lala did not get angry and see shadows of Hiroki on Nagate. However, in the end she was still angry, but to Izana.
The times to come to ERD facility, the Gauna's placenta sample retrieved by Nagate is revealed to have the same appearance as Shizuka Hoshijiro, and while in containment, it utters some words including Nagate's name.