In an old mine outside Reno, a rancher named Eddie, Richard Marion discovers a large mutated sheep embryo. Professor Clemens E. Kerrigan Prescott and his assistant Mariposa Karen Ingenthron take the embryo back to their laboratory, where Clemens explains that he came to the area to investigate the mines because of a local legend about a monstrous presence that haunts the region. He suspects that phosphorus vapors escaping from the mine may have triggered the mutation, and he places the embryo in an incubation chamber, where it begins to grow into an eight-foot-tall mutant sheep monster.
Meanwhile in town, a wealthy East Coast entrepreneur named Barnstable, Christopher Brooks, seeks to buy land for mining development on behalf of his employer Rupert Reich. He runs into fierce resistance from Mayor Charles Silverdale Stuart Lancaster, who wants to preserve the town as a destination for Old West tourism. The mayor orchestrates a smear campaign, framing Barnstable for killing a dog (a ruse tied to events in Albuquerque) and stirs a mob that moves to lynch him. Barnstable manages to slip away from the angry crowd.
The monster escapes from Clemens’ lab and begins roaming the surrounding area, terrorizing children, unsettling residents, and even driving a man to blow up his own gas station. After a tense pursuit, the creature is captured, and the mayor schemes to expose it as the “Eighth Wonder of the World.” However, the plan backfires—the townspeople grow angrier because they feel their land claims have been betrayed rather than celebrated, and their anger turns into a dangerous frenzy. The crowd pushes several cars off a cliff and into a garbage dump, including one that carries the Godmonster in a cage.
The cage-bearing vehicle plunges into the garbage dump, and the Godmonster explodes as Barnstable flees the scene. In the final moments, the camera hints at a troubling future as more mutant sheep are born, while Mayor Charles Silverdale rants and clings to his turf battle, leaving the town to confront the consequences of fear, greed, and unchecked power.
