It is 1991, three years after a spacecraft carrying 300,000 enslaved aliens lands in the Mojave Desert. Most, called Newcomers, live in Los Angeles. Tough Police Detective Matthew Sykes (James Caan) loses his partner in a shootout and is matched with the first Newcomer detective Sam Francisco (Mandy Patinkin). Sykes does not like the Newcomers but thinks he may be able to investigate his partner’s death, which he is not supposed to do, because the case that led to his partner’s death was a murder involving Newcomer on Newcomer crime.

In a crime lab, Francisco detects an abnormality on the body of a Newcomer victim. Later, they investigate a clue in a nightclub, and they interview the victim’s girlfriend. They are suspicious of a successful Newcomer businessman named William Harcourt (Terence Stamp). He is producing a drug that pacifies newcomers and was used to enslave them, though it has no effect on Humans. After a car-chase and some other cop-show business in downtown LA, Harcourt overdoses on the drug. They think he has died, but he mutates into a more powerful Newcomer.

They pursue him and catch up with him at a fishing pier. Saltwater is poisonous to Newcomers. Harcourt dies in the ocean and Detective Francisco injures himself to save Sykes from drowning. Sykes and Francisco attend Sykes’s daughter’s wedding.

The script was by prolific TV writer Rockne S. O’Bannon and produced by Gale Ann Hurd. It is a Neo-Noir Buddy-Cop Science Fiction Action Film, directed by Graham Baker. It spawned a short-lived TV series, five TV movies, novels, and comic books. Hurd was intrigued by the alien immigrant story. The makeup by Stan Winston Studios of the Newcomers, and their written language on signs, etc., took a long time to design and create. Filming in well-known Los Angeles locations gave it a certain realism. After a while, one almost forgot that the Newcomers were alien. The story was partly inspired by In the Heat of the Night and the Outer Limits TV anthology.

A score for the film by Jerry Goldsmith was not used, except in the trailer, because it was thought too weird. Songs by Smokey Robinson, The Beach Boys, Michael Bolton, Mick Jagger, and David Bowie were used in the film. It received mixed reviews, some complaining that it was too much cop-story and not enough science fiction. Sam Francisco was originally supposed to be called George Jetson, but they couldn’t get permission from Hanna-Barberra. This was the first screenplay by Rockne S. O’Bannon, who wrote and/or produced for Amazing Stories, The Twilight Zone, Seaquest, Farscape, Warehouse 13, V, Constantine, and Evil.