Dr. Adrian Helmsley, part of a worldwide geophysical team investigating the effect on the earth of radiation from unprecedented solar storms, learns that the earth's core is heating up. He warns U.S. President Thomas Wilson that the crust of the earth is becoming unstable and that without proper preparations for saving a fraction of the world's population, the entire race is doomed. Meanwhile, writer Jackson Curtis stumbles on the same information. While the world's leaders race to build "arks" to escape the impending cataclysm, Curtis struggles to find a way to save his family. Meanwhile, volcanic eruptions and earthquakes of unprecedented strength wreak havoc around the world.

Thirty years ago, aliens arrive on Earth. Not to conquer or give aid, but to find refuge from their dying planet. Separated from humans in a South African area called District 9, the aliens are managed by Multi-National United, which is unconcerned with the aliens' welfare but will do anything to master their advanced technology. When a company field agent contracts a mysterious virus that begins to alter his DNA, there is only one place he can hide: District 9.