In the heart of Houston, Texas, a series of bizarre, violent deaths begin to puzzle the local police department. Detective Jack Caine, a tough, rule-breaking cop, finds his investigation into these strange occurrences sidetracked by a series of drug-related crimes plaguing the city. Determined to get to the bottom of the deaths, Caine's world is turned upside down when he discovers that the culprits are not human. The city becomes the battleground for a deadly interstellar conflict involving an alien drug dealer who has come to Earth to harvest endorphins from human brains, a substance that is a valuable narcotic on his planet.

Caine is forced to partner with Arwood "Larry" Smith, a straight-laced FBI agent who is as much by the book as Caine is against it. Together, they embark on a perilous mission to track down and stop the alien perpetrator. As they delve deeper into the investigation, they uncover an intricate web of corruption and alien technology beyond human comprehension. The unlikely duo must navigate the dangerous terrain of drug cartels, federal interference, and an increasingly hostile alien adversary, setting the stage for an explosive confrontation that threatens not only their lives but the entire city. Their journey challenges their beliefs, their strategy, and their very survival, pushing them to the limits in their fight against the extraterrestrial menace.