Years after the events of the first film, Earl Bassett has moved away and squandered his fortune on a failing ostrich ranch. He is approached by Carlos Ortega, who informs him that Graboids are killing workers at his oil field in Chiapas, Mexico, and hires him to hunt them down. Earl initially declines, but Grady Hoover, Ortega's taxi driver, convinces him to change his mind after mentioning that Ortega will pay $50,000 for each Graboid killed; both join the hunt. Upon arrival, Earl learns that the company would pay him double if he caught one of the creatures alive. He also meets Kate Reilly, a geologist, her assistant Julio, and a mechanic named Pedro, all of whom are scientifically investigating the Graboids.
[Earl] Bassett and [Grady Hoover] begin systematically killing the Graboids by using remote-controlled cars rigged with explosives. The early results seem promising, but the vast numbers soon overwhelm them. To turn the tide, Earl calls in Burt Gummer, who arrives driving a rugged deuce-and-a-half truck stocked with firearms and extra explosives. The following day, a Graboid ambushes their setup, sending the truck careening into an inclined ditch. Returning to the scene, they discover the creature looks sick and its tentacles appear dead, leading them to believe they have one alive—the kind of sample Ortega promised a hefty reward for. Yet the Graboid later dies, leaving a gruesome hole in its body. They spot Pedro’s truck approaching in the distance, but it stops abruptly and its engine is destroyed, with Pedro’s remains found nearby. The group then makes their way to a nearby radio broadcasting building, which has also been shattered, and they encounter strange, bipedal, graboid-like creatures. Earl manages to kill one as it charges, and the trio flees in a car they had found as more of these new beings converge. Burt’s truck is ambushed by a pack of the intruders on the way back to base.
The next morning, the threat reaches the oil refinery, where Julio is violently killed by one of the new creatures. Grady and Earl arrive just in time to shield Kate from an attack, with Burt arriving shortly after in another tense firefight that leaves him low on ammunition. Through experimentation, the group discovers that these creatures—now dubbed Shriekers—are hermaphrodites capable of rapid reproduction after consuming sufficient food. They also learn that the Shriekers cannot hear; instead, they see heat through infrared receptors on their heads. However, the threat proves relentless as the Shriekers discover Burt’s MRE food supply and multiply at a staggering rate. They launch an attack on the refinery area and reach Julio, who is killed in the chaos. The team tries to maneuver to safety, but Burt’s vehicle is disabled during a failed attempt to escape.
Hiding from the rapidly advancing threat, Burt becomes trapped in a bulldozer bucket while Grady, Kate, and Earl seek higher ground atop an oil tower. The Shriekers coordinate a climb toward them, and a tense sequence unfolds as they attempt to trap the creatures in a storage shed with Burt’s truck. Inside, their plan hinges on rice flour stored nearby, which allows the Shriekers to keep feeding and multiplying. Earl covers himself in CO2 from a fire extinguisher to mask his body heat and searches Burt’s supplies for the detonator. The plan hinges on timing, as the CO2 effect fades and the Shriekers regain their ability to detect heat, forcing Earl to hurl the detonator into the supplies before escaping. The group narrowly escapes as a massive explosion devastates the facility, destroying the Shriekers in one final, explosive act.
In the aftermath, Earl and Kate decide to pursue a romantic connection, while Grady suggests turning their experiences into a monster-themed theme park, capitalizing on the money Ortega now owes them. The movie closes with the sense that the surviving group has found a way forward, using their survival ordeal to imagine new directions in a world where the creatures have proven both dangerous and economically game-changing.
