The narrative unfolds in Los Angeles during the year 1991. Three years prior, an alien vessel made a crash landing on Earth, revealing itself to be home to 300,000 "Newcomers," an extraterrestrial workforce stranded with no means to return to their home planet. Initially quarantined, these beings were eventually allowed to coexist alongside humans in the LA area.
The story centers on Detective Matthew Sykes and his partner, Detective Tuggle, who are on patrol in a Newcomer neighborhood. When they witness two aliens clad in long black coats entering a convenience store, the situation swiftly escalates. Armed with shotguns, the aliens rob the store's owner, prompting an intervention from Sykes and Tuggle. A fierce gunfight breaks out, resulting in Tuggle being struck fatally by a powerful shotgun blast that penetrates the car he is hiding behind. Incensed by his partner's death, Sykes pursues the assailants with vengeance.
Venturing into a dark tunnel, Sykes confronts one of the Newcomers who has taken a mysterious blue fluid. After a violent encounter, Sykes ultimately shoots the alien, who initially appears unfazed but eventually collapses. When assistance finally arrives, Sykes reacts violently upon discovering that one of the officers is a Newcomer, showing his deep-seated prejudice toward the alien race.
The following day, at their headquarters, the team mourns Tuggle's demise during a debriefing. The captain announces the inclusion of a Newcomer detective, and Sykes, despite his biases, offers to take on the alien as his new partner. This Newcomer, who has adopted the vernacular name Sam, quickly earns the nickname "George" from Sykes, who refuses to accept his full name of "Sam Francisco."
As the duo investigates, they visit the coroner's lab where they learn about the slain Newcomer store owner and the alien that Sykes shot. While Sykes engages with the coroner, George converses in his native language with his assistant, revealing a sense of unease about their findings, particularly a condition linked to the murderer that he withholds from Sykes.
The investigation leads them to Joshua Strader, a nightclub owner in peril. Strader is being brutally attacked by the henchmen of a Newcomer businessman named William Harcourt, while his assistant, Rudyard Kipling, looks on anxiously. Harcourt, intent on coercing Strader into a deal, orders his men to take him into the salt water — a substance detrimental to Newcomers just as acid is to humans.
Delving deeper, Sykes and George uncover that Strader shared quarantine with Harcourt and two other chemist Newcomers. Their inquiry takes them to a factory where Newcomers operate in an atmosphere filled with methane gas unharmed, showcasing the strange dynamics of their existence. After leaving, the factory manager peeks behind protective glass at Newcomers working on a complex production of the blue fluid that one of the robbers had consumed prior to their encounter.
Through these unfolding events, the harsh realities of prejudice, rivalry, and survival are starkly illuminated on the streets of Los Angeles.
