Hick handymen Val McKee and Earl Bassett can barely eke out a living in the Nevada hamlet of Perfection, so they decide to leave town -- despite an admonition from a shapely seismology coed who's picking up odd readings on her equipment. Before long, Val and Earl discover what's responsible for those readings: 30-foot-long carnivorous worms with a proclivity for sucking their prey underground.

When an army of Graboids - giant, carnivorous underground worms - threaten the Petromaya oil refinery in Mexico, its owners call on Earl Bassett, who once helped kill four of the creatures in Perfection, Nevada. Having squandered the money that came from his resulting celebrity status, Earl is convinced by the $50,000-a-head bounty offered, as well as the enthusiasm of admirer Grady Hoover, who becomes his partner. At Petromaya, Earl and Grady meet geologist Kate Reilly, and begin Graboid hunting, tricking several Graboids into swallowing bomb-rigged, remote-controlled cars. When they find they're facing a lot more Graboids than they ever expected, Earl calls his friend Burt Gummer, a survivalist who arrives well-stocked with weapons.

Burt Gummer returns home to Perfection, Nev., to find that the town of terror has become a theme park, and when the simulated giant worm attacks turn real, the survivalist must battle the creatures once again. Gummer pits his impressive knowledge of weaponry against the newest and deadliest generation of flesh-eating graboids, with help from two young entrepreneurs.

This prequel of the bone-chilling Tremors begins in the town of Rejection, Nev., in 1889, where 17 men die under mysterious circumstances. Spooked by recent events, the miners who populate the town leave in droves until there's nothing left but a shell of a community. It's up to the remaining residents to get to the bottom of the deaths -- but they must do so before they, too, are eradicated off the face of the planet.