Alien Nation (TV series) was a television show from the Fox Network which lasted a single season, ending in 1990 with a cliffhanger series finale. Dark Horizon was written to be the season opener for the second season, but when the series was unexpectedly canceled and looked like it might never return to television, the plot was published as a book. Finally, four years later (after a change in management at Fox), Alien Nation: Dark Horizon (original airdate: October 25, 1994) appeared as a television movie to pick up where the popular television series left off.

Alien Nation: Dark Horizon was written by Andrew Schneider & Diane Frolov, and was directed by Kenneth Johnson.

Followup movie to the TV series about 250,000 aliens, or "newcomers" as they are known, who have by now settled alongside the humans in California. Most of the newcomers were slaves, and the slave masters are now looking for them. They send Aponso to earth to locate the slaves ready for the aliens to pick them up. Written by Rob Hartill

Picking up where the "season finale" left off, Emily and Susan are on life support after being contaminated with a virus, which is found to be from a Purist group. The Purists have created a mass of it to spray over LA to kill all Newcomers. At the same time, an elite Overseer arrives to organize the return of the Tenctonese to slavery, and decides to take the human population as well. Written by Michael Bennett