Exposition
The story of Terra e... is the story of Earth. It's about two sides; the humans and the Mu people. One side tries to eliminate the other and prevent them from reaching Terra, the Earth. The other side only has one hope, one dream, to return home, to return to Terra.
The anime takes us behind both sides; the good and the bad. Though honestly speaking, it's hard to say there is a bad side. What we really see are two groups with vastly different ideals which happen to conflict.
We start off from the side of the Mu, as we follow in Jomy's awakening. Jomy Marquis Shin is the protagonist, he is the one who propels the story forward. But we quickly see the story through Keith's point of view, as we are brought to his youth we see how he grows. Keith Anyan is the antagonist; he serves to bring conflict against Jomy and the Mu people.
Throughout the episodes, we see the great differences between humans and Mu, Keith and Jomy. While Keith grows ever older, and more powerful in position, Jomy, as a Mu, remains virtually the same physical age and does not change in power, he is always Soldier.
I've talked quite an amount about the Mu. Who are they? They are people who have evolved further than humans and possess great psychokinetic powers. They are banned from human society and are hunted. They are the enemy of the Superior Domination system, which rules human birth and every aspect of human life. And they have one goal, to return to their mother, to their home, to Terra.
As for the way the episodes move, we go back and forth between the Mu people and the humans. We really are shown both sides and we are also shown there is no real enemy, at least in the form of a living person.
The underlining point of Terra e... is to remind us that our home, the Earth, the Terra, is precious and should be treated with care and not abused and wasted. We need to keep our planet blue.