Adventurer Burt Gummer returns to his hometown of Perfection, Nevada, after a hunt for Shriekers in
El Chaco,
Argentina. Since
the original Graboid attacks, the town's preventive equipment for tracking Graboid activities has fallen into disrepair due to the neglect of native residents Miguel, Nancy Sterngood, and her daughter Mindy. Walter Chang's market has been taken over by his niece Jodi, and the town has gained a new resident, Jack, who creates mock-attack tours for visiting tourists. One afternoon, during one of Jack's tours, his assistant Buford is eaten by an actual Graboid. Jack, Mindy, and Jack's customers manage to escape to warn the town, and Burt determines there are three Graboids in the area. The residents begin taking action to kill the Graboids, but they are stopped by government agents Charlie Rusk and Frank Statler and a
paleontologist, Dr. Andrew Merliss, who claim the Graboids are an
endangered species, thereby preventing the humans from hunting them. Jack manages to reach an agreement with the agents that if they capture one live Graboid, Burt and the residents will be allowed to kill the remaining two. Burt grudgingly agrees, and he and Jack set out to trap a Graboid while the agents go after another of their own accord. Melvin Plugg, a fellow survivor from the original attacks, approaches Burt in the hopes of buying his land and developing it into a town. After he refuses, a Graboid attacks and swallows Burt whole. Jack lures the Graboid to Burt's home, having it fatally collide with the underground concrete barriers surrounding the building. He then uses a chainsaw to free Burt from its belly. Burt, Jack, Jodi, and Miguel later find a badly wounded Merliss; before dying, he explains that he and the government agents were ambushed by Shriekers from the Graboid they were chasing. While tracking the Shriekers, an
albino Graboid — later named El Blanco — traps them on rocks for the night. Miguel deduces El Blanco can't produce Shriekers because it's infertile. After drawing El Blanco away, they find that the Shriekers have molted their skin, becoming winged creatures capable of rocket-propelled flight. Miguel is killed by the creature, which then crashes into a metal fence, killing itself. Burt realizes that chemicals in their stomachs react explosively, enabling their flight. Finding them capable of carrying Graboid eggs, they surmise that they evolved to spread them by flight. Jodi dubs the new form Ass-Blasters. Meanwhile, Nancy and Mindy are attacked by an Ass-Blaster in town and hide in a freezer while distracting it with food. Using a mattress as cover from the Ass-Blasters' infrared vision, the group gets to Burt's house, but is forced to flee when an Ass-Blaster attempts to break in. To keep it from multiplying like its predecessors, Burt rigs his house and his stash of
MREs to explode, killing it; however, it is only after that that they learn from Nancy that Ass-Blasters do not multiply but fall asleep after eating, as has happened to the one that attacked her and Mindy. The group flees to a junkyard, where they build a
potato gun from everyday objects to ignite the combustible materials in the Ass-Blasters' stomachs. After they kill four, Burt is attacked by El Blanco and pinned down. Realizing that Burt's ultrasonic watch is repeatedly drawing El Blanco to them, Jack takes it and sticks it to the final Ass-Blaster. El Blanco devours it, saving Burt and Jodi's lives in the process. In the aftermath, Nancy manages to sell the captive Ass-Blaster, while Jack pursues a romantic relationship with Jodi, depressing Mindy, who had a crush on him. Meanwhile, Melvin tries again to approach Burt about selling his land, but Burt informs him that since El Blanco is an endangered species and illegal to hunt, and formed a mutual unspoken friendship with Burt, the residents have decided to take precautions in order to live safely alongside it, thus turning Perfection into a federally protected Graboid reserve and barring Melvin from developing a town. Burt then leaves Melvin standing on a rock with El Blanco circling below. ==Cast==