In Rockne O'Bannon's screenplay for Alien Nation, the background for the story line is that five years earlier a spacecraft containing 250,000 Tenctonese slaves who have been genetically engineered for hard labor, had crashed in California's Mojave Desert. As fans of the film and subsequent television series are aware, the Tenctonese, or Newcomers as they're commonly called, are stronger and smarter than the humans on Earth, and generally appear humanoid with the exception of slightly larger skulls that are adorned with a variety of spots. We also learn that they eat raw meat in the form of a variety of animals, their bodies react to salt water as our would to acid, and the most sensitive areas on their bodies are the armpits.
After a brief quarantine on Earth, these beings are given human names (most of them groan-inducing, such as Jim Nasium) and integrated into human society. At first humanity is fearful, but ultimately accepts them as Earth's newest minority.
"Many science fiction films have touched on different aspects of alien landings," says O'Bannon. "I thought it would be interesting, instead of building up to the first meeting with an alien race, as in Close Encounters of the Third Kind, if you showed what might happen three years after that. When I sat down to write, and I was thinking budgetarily, I didn't want to write a huge science-fiction piece. I wanted something that was extremely accessible, that made it far more real the idea that if in fact an 'out there' set of circumstances about a single ship, without any connection to where it came from, were to come into our solar system, all of the initial awe and amazement and fear would eventually subside.
"We tend to be able to adapt to just about anything. Eventually we'd be faced with the conflict of 'What do we do?' The idea is that the ACLU would come to the fore and say, 'We can't just leave them up there in the ship forever. They've been proven not to be dangerous to us, can we put them in a period of quarantine? We need to allow them to integrate with us.' To me that was kind of an interesting jumping-off point."