Alien Nation: Dark Horizon (original airdate: October 25, 1994) is a television film made as a continuation of the Alien Nation television series. Produced by the Fox Network, Alien Nation 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 appeared as a television film to pick up where the television series left off.
Alien Nation: Dark Horizon was written by Andrew Schneider and Diane Frolov, and was directed by Kenneth Johnson.
In a recapitulation of the series cliffhanger, Alien Nation: Dark Horizon begins with Susan Francisco and her daughter Emily falling victim to a newly developed viral infection that was created by a group of human Purists to exterminate the Newcomer species. There is also a new sub-plot running parallel to this one, the story of Ahpossno, a Tenctonese Overseer who lands on Earth to find any surviving Tenctonese and bring them back into slavery. The idea of a signal sent into space by the surviving Overseers was explored in the Alien Nation episode Contact.
(The series episode ended with contaminated flowers being delivered to the Francisco family and Cathy informing Matt that they have been hospitalised. However Dark Horizon seems to retcon the end of the previous episode by having similar events taking place at the beginning of the episode which seems to be set 4 years later.