A lot of revelations in this episode. The anti-spiral tribe is afraid of change, and because of that it wants to destroy all advanced civilizations from the spiral planets (which apparently means all the planets that exist within a spiral shaped galaxy, like the Milky Way).
According to Nia’s speech, she won’t change back to her Human form. That means we lose the main girl, and I think that leads to Yoko’s return. The humans became selfish and arrogant, they demand compensation for their houses and they accuse the government for the future moon crash, with that in mind it’s kind of understandable with the anti-spirals want to kill us so badly. We’re just too damn rotten and spoiled.
Simon was arrested for recklessly fighting The Mugan, and even though it worked Rossiu is a perfectionist and for him such behaviour isn’t allowed leading to him getting arrested and giving up the core drill.