When the peaceful inhabitants of the planet Terra come under attack from humans in search of a new home, the friendship between a human pilot and an alien girl may hold the key to saving both races. Mala (Evan Rachel Wood) is an alien girl living on the planet Terra. The Terrians are gentle race of extraterrestrials that have no need for war, and harbor a deep respect for nature. When Earth's natural resources began to dwindle, the human race established colonies on Venus and Mars. Although that solution worked temporarily, tragedy struck when the colonies on Venus and Mars attempted to declare independence from Earth, and all three planets were destroyed in the ensuing war. Now, humankind's only hope for survival is to reach Terra. The few remaining humans have developed a machine that will make Terra habitable for them yet poisonous for Terrians, and while the human council is dedicated to finding a peaceful means of coexisting with the Terrians, the villainous General Hemmer (Brian Cox) is fast losing patience. When heroic human fighter pilot Lt. Jim Stanton (Luke Wilson) crash-lands on Terra while chasing Mala into uncharted territory, the empathetic alien girl saves his life, and an interspecies friendship is forged. But time is running out for both the humans and the Terrians, and when General Hemmer stages a military coup d'état, the stage is set for a battle that threatens to destroy both species.