At first, Stanton is suspicious of the Terrans, but as Mala shows him kindness, he warms to the planet.
Stanton returns to his mother ship and we learn that the humans on it have been wandering the galaxy for generations, looking for a suitable planet to colonize. It seems war and environmental mismanagement destroyed Earth, forcing mankind out into the stars.
Stanton tries to tell Gen. Hemmer (Brian Cox, "The Water Horse") that the Terrans will likely help them, but Hemmer is of the manifest destiny, us-vs.-them mind-set that has characterized colonialist foreign policies for so long.
What follows is a showdown that takes a different shape than one would expect. The Terrans seem helpless and naive, but we find they have a violent past of their own.
While it has its preachy parts, "Terra" balances its warm and fuzzy environmentalism with some thought-provoking statements about antiauthoritarian individualism, balance between nature-worship and the protection of self-interest, and the folly of thinking the power of force can be completely banished in favor of hanging out with sky whales.