CGI-animated sci-fi adventure. Alien teenager Mala (voiced by Evan Rachel Wood) lives a quiet, harmonious existence on a beautiful and peaceful planet known as Terra. Unbeknownst to Mala and her fellow Terrians, the last inhabitants of Earth have finally exhausted the resources of their planet - and those of three others - and are on the lookout for a new home. To this end, they have invented the 'Terraformer', which will make Terra habitable for humans but poisonous for Terrians. When the Earthlings invade Terra, Mala's father Roven (Dennis Quaid) is kidnapped. While trying to save him, Mala captures and hides a crashed human pilot called Jim (Luke Wilson). As Mala is nursing Jim back to health, the two forge a friendship - and hatch a plan that could save both the planet of Terra and the human race.