As the monolith collapses, the gastrea attack the JASDF, which while initially successful quickly loses out to the Gastrea. Rentaro spots a detachment of Gastrea moving to flank the civil officer contingent and his adjuvant disobeys orders to neutralize it. Upon their return, they find that the Gastrea are quickly marching forward and the contingent has been overrun. He discovers Gado's son, shell shocked, talking about a "Spear of Light". After Gado's son is eaten, the "Spear of Light" reappears and destroys much of what remains of the force. Mysteriously, after Aldebaran is hurt the Gastrea retreat, leaving the survivors. After resettling, Rentaro is called to a meeting with Commander Gado. After Rentaro suggests killing Aldebaran will win them the battle, the commander reveals that he believes that Aldebaran is immortal and the only way to beat back the advance is to defeat a new stage four Gastrea code-named Pleiades, who is capable of generating large amounts of mercury. He then disbands Rentaro's adjuvant and sentences Rentaro to a suicide mission to kill Pleiades. Rentaro attempts to leave without telling anyone, but is subsequently stopped by Kisara. After he convinces her, he leaves but is attacked by a pack of wolf Gastrea. He is then surprisingly saved by Kagetane, who it seems was not actually dead. Despite his mistrust, Rentaro stays the night with them, and refuses an offer to join them, upon which Kagetane predicts he will. After the night, Rentaro begins to leave, upon which Kagetane steps in and tells Rentaro he has saw Pleiades up the river. Thus the three (with Kagetane and Kohina "happening to go the same way") head upstream.
| Name | Type | Role | |
|---|---|---|---|
| Tatsuhiko Urahata | Writer | Series Composition | |
| Kurasumi Sunayama | Writer | Screenplay | |
| Masayuki Kojima | Director | Series Director | |
| Hiroshi Ikehata | Director | Episode Director |