"Los Angeles, 1991. They have come to earth to live among us. They've learned the language. Taken jobs. And tried to fit in. But there's something about them we don't know. Prepare yourself."
Alien Nation, a buddy cop film released in 1988, starred James Caan as detective Matthew Sykes and Mandy Patinkin as alien detective George Francisco. In this movie, an alien race, referred to as Newcomers, tries to settle in Los Angeles, against the wishes of the local population.
Detective Sykes' partner is killed by aliens, also referred to as "Slags", in a Slagtown shootout. The police department hires Francisco to help find crime, and Sykes volunteers to work with him in hopes of finding justice for his old partner. During their criminal investigations, the duo discover a plot by a major criminal kingpin (a Slag named William Harcourt) to drug the entire Newcomer race with a powerful narcotic.
After a chase and crash, it is thought that Harcourt has been killed. However, after overdosing on the narcotic, Harcourt morphs into a super Slag with his mind set on havoc. After a fight with Sykes, Harcourt croaks after coming into contact with salt water, which is deadly to the Slags. In the end, the bad guy dies, the good guys live, and become fast friends. This movie was popular enough to warrant a spin-off TV series in 1989, but it only lasted for 1 season (22 episodes). In addition, there were a number of made for TV movies throughout the 1990's.