Captain plays racquetball alone, and both Lieea and Maaie notice that he’s bothered by missing a ball. They know that he feels bad about their enemy now being the Mu. Kei receives a massage from Mome and asks about how Captain is doing. She tells him about Captain’s depression, and when he asks how she feels, she answers that today’s Mu are too different from before for her to fit in. Mimsy asks Kei to help with her luggage and jokes that he’s an old man if he needs a massage from Mome. Elsewhere, a group of Mu robots warp into an Emaan city and start attacking civilians. Several Deemoras launch and attack the Mu. Shaya picks up the attack on sensors and orders everyone to scramble. A combined Chiram/Emaan force led by Athena and Kei attacks the Mu forces in an open field. Drifand Dal and Logwood artillery mecha provide support fire, but quickly become targets themselves. Captain watches the battle and tells Mome that he’s going to leave. Mome asks Captain to take her with him because Kei has Mimsy now. She also says that the war will never end as long as the Mu have the warp system, so they leave in a small hovercraft. Maaie and Lieea spot their departure as they warp out with other Mu. Inside the Mu city, they’re confronted by a robot, so Captain lies that he was injured and came back with Mome, his maintenance robot. The other robot notes that Mome’s type is rare and was discontinued long ago. Kei laughs when he hears the news from Maaie and Lieea about Captain and Mome leaving. Shaya and Mimsy couldn’t find them anywhere, so Kei wonders if they really did leave. Captain and Mome are transported to headquarters, although Mome is told to stay behind. A robot tells Captain that living creatures should be banished, but Captain notes that they’ll eventually wipe each other out. The other robot agrees, but states that they’re trying to repair the planet, which would rob the Mu of all the time and space they currently control. In another room, a robot creeps up behind Mome and frightens her.
The robot explains to Captain that the warp system manipulates space-time, so they can use it control history. Captain asks about negative consequences, but the robot says they don’t matter, which upsets Captain. Captain is shown the warp system and asks about exploring other planets, but the robot answers they have no interest in that. Another robot explains that they only need the new gravity energy frequency converter to travel as they have been. Captain asks where Mome is, and when one of the robots explains she was replaced as waste, Captain punches it and runs away. In a ruined area outside the city, Captain encounters several robots attacking another robot of Mome’s type. Captain destroys two of the robots and is told by the third that humanoid robots are put in a prison camp. Elsewhere, Mome hides in the ruins to escape the chasing robots. One of the robots targets her and is destroyed by Captain. After Mome passes out, Captain is filled with anger and destroys all the attacking robots. Captain asks Mome why the Mu are destroying humanoid types, so she explains that in this world, the Mu started annihilating humans a century ago in rebellion. After that, they turned their attention to destroying humanoid robots. Mome asks what they should do, and Captain responds that he wants to destroy the warp system. They break into the facility and trip an alarm, so Captain tells Mome to handle the system while he fights. Captain unleashes missiles and destroys multiple attacks, but reinforcements arrive and force him to fall back. He then fires a massive energy beam that destroys them and leaves him weakened. Mome reports that after they leave, the system will destroy itself. Captain is blasted from behind by a robot and punches it. The warp field begins to form, so Mome tackles the other robot. After they vanish, the warp field sets off a massive explosion inside the building. Mome and Captain reappear in the open field and are spotted from above by Kei’s Orguss. Kei hugs Mome and tells her that she had him worried. Captain tells thinks that humans and robots should coexist in peace.
With the Mu now becoming the main threat, the series places some much needed focus on the cast’s two Mu characters. Captain and Mome both find themselves in a state of depression, albeit for different reasons. Captain feels ambivalent about fighting his own people, and Mome feels down because Kei loves Mimsy rather than her. So they impulsively set off on a mission to infiltrate the Mu city and destroy the warp system, which provides the Mu with a devastating advantage. We learn that the Mu come from the cliche background of being robots that exterminated their human masters, and now they want to eliminate organics to maintain supremacy over the fractured Earth. They’re also so anti-human that they’ve taken to eliminated humanoid type robots like Mome. This situation gives Captain new determination, so he steps up to fight his own people and help destroy the warp system. Having taken this trip together, the two return to the Glomar stronger and out of their depression. Given that the last episode basically did nothing, it was good to see the story advance through the eyes of supporting characters rather than Kei.