THE MONOLITH MONSTERS

In the desert outside of San Angelo, California, a meteorite crashes, scattering hundreds of black fragments. The next day, Federal geologist Ben Gilbert brings one of the fragments to his office. He and local newspaper publisher Martin Cochrane examine it. That night, a strong wind blows over a full water container onto the black rock, starting a chemical reaction.

Dave Miller, the head of San Angelo's district geological office, returns from a business trip and finds Ben's corpse in a rock-hard, petrified state and the office's lab damaged by rock fragments. Dave's girlfriend, teacher Cathy Barrett, takes her students on a desert field trip; young Ginny Simpson pockets a piece of the black meteorite rock, later washing it in a tub outside her family's farmhouse. In town Dr. E. J. Reynolds performs Ben's autopsy and cannot explain the body's condition; he sends the body to a specialist. Martin returns to the wrecked office with Dave, where he recognizes the fragments as the same type of black rock Ben had been examining.

Cathy joins them, also recognizing the fragments. They go to the Simpson farm, which they find in ruins under a pile of black rocks. Ginny's parents are dead, and Ginny is in a catatonic state. At Dr. Reynolds' request, they rush her to Dr. Steve Hendricks at the California Medical Research Institute in Los Angeles. He reports that Ginny is turning to stone. Dave brings a fragment to his old college professor, Arthur Flanders, who determines that it came from a meteorite. Back at the Simpson farm, both men notice a discoloration in the ground; tests show the black rock is draining silicon from everything it touches. Dr. Reynolds says research indicates that one possible function of silicon in the human body is to maintain tissue flexibility. They realize that absorption of silicon is the cause of Ben's death and Ginny's condition.

Dave and Arthur trace the fragments to the crashed meteor. Arthur deduces that the meteorite's atomic structure has been radically altered by the intense heat of atmospheric friction. In the meantime, Dr. Hendricks administers a silicon injection to Ginny. Back in the lab, Dave and Arthur investigate why the black rocks seem to be multiplying. A piece of black rock falls into the sink and reacts when coffee is poured on it; the men then realize that water is the cause of its growth. With a rainstorm now in progress, they return to the desert and see the black fragments growing into stories-tall monoliths that collapse under their own weight, breaking into fragments, each fragment then repeating that cycle. Dave realizes that the monoliths' path will take them directly through San Angelo, and from there the monoliths could spread and possibly threaten all life on Earth.

They explain the threat to Police Chief Dan Corey, who makes plans to evacuate San Angelo. The governor is notified, and declares a state of emergency in the San Angelo area. At the hospital, Ginny revives, and Dave deduces that something in the silicon solution will check the fragments' growth. More locals are rushed to Dr. Reynolds' office in various stages of petrification. With little time left, and the telephone and electricity cut off, the monoliths continue to multiply and advance, soaking up water from the rain-soaked soil. Through lab experimentation, Dave and Arthur discover the monoliths can be stopped with a simple saline solution, a part of Steve's silicon formula.

Dave plans to dynamite the local dam and flood the nearby salt flats, creating a large supply of salt water. Because the dam is private property, Dan attempts to contact the governor for permission to blow up the dam. Knowing they must halt the monoliths at the canyon's edge, Dave acts without waiting for the governor's approval. A torrent of water flows over the salt deposits at the canyon's edge, reaching the monoliths; their growth is halted. Dan reports that he reached the governor who told him not to blow up the dam ... unless Dave was absolutely certain of success. Dave comments on Martin's earlier assertion that the region's salt flat was "Mother Nature's worst mistake," pointing out that this near-disaster has proved otherwise.

The townspeople discover the way to neutralize the monoliths, stopping their spread and averting the threat to San Angelo and possibly the world.

The resolution hinges on scientific ingenuity and quick action, underscoring the film’s classic 1950s faith in rational problem-solving amidst chaos. By confronting the runaway geological disaster with a collective community effort, the film offers a reassuring conclusion to its exotic menace.