The Monster That Challenged the World (1957) Plot Summary Explained

An underwater earthquake at the Salton Sea opened a deep crevice in the lake bed that had been sealed for millions of years. This geological disturbance released prehistoric giant molluscs that had been trapped underground into the open water, allowing them to escape and begin their reign of terror.

• earthquake
• salton sea
• molluscs
• prehistoric
• release

When one sailor from the patrol boat dove into the water to investigate, he disappeared entirely. His body later surfaced blackened and completely drained of bodily fluids, showing the deadly effect of the molluscs' slime on human tissue.

• sailor
• dive
• death
• mollusc slime
• body

The Navy kept the giant egg under strict temperature control to prevent it from hatching. The lowered temperature essentially put the embryo inside into a dormant state, slowing its development and keeping it from maturing into a active creature.

Foreshadowing: The egg's temperature sensitivity was established early when scientists placed it under controlled conditions to study it safely.

• egg
• temperature
• hatching
• embryo
• dormant

The molluscs managed to escape from the controlled Navy environment and entered the irrigation canal system that runs through the agricultural regions. From there, they spread outward and began attacking livestock and people in the surrounding areas.

• molluscs
• escape
• irrigation
• canal
• spread

Sandy, worried about the lab rabbits getting cold in the lowered temperature, secretly adjusted the thermostat. The resulting temperature increase removed the cold-induced dormancy holding the embryo in check, allowing the giant mollusc inside the egg to finally hatch.

Foreshadowing: Earlier, scientists explicitly stated that temperature control was keeping the egg from hatching, establishing the direct cause-and-effect relationship.

• sandy
• thermostat
• egg
• hatch
• temperature
• warming

When Twill arrived to find the hatched mollusc cornering Gail and Sandy in a closet, he fought it using whatever was available in the laboratory. He attacked it with laboratory chemicals, a CO2 fire extinguisher, and finally a live steam line until Navy reinforcements arrived and shot the creature to death.

• twill
• fight
• mollusc
• fire
• steam
• laboratory
• battle

The strange slime was a secretion produced by the giant molluscs. It was highly corrosive and toxic, capable of blackening and draining the bodily fluids from human victims upon contact, leaving them completely desiccated.

• slime
• secretion
• toxic
• corrosive
• drain
• body fluids

The rabbits served as test subjects in the Navy laboratory studying the molluscs. Their presence created the reason Sandy was worried about the cold when the thermostat was lowered, which led her to secretly turn it back up and accidentally trigger the egg's hatching.

• rabbits
• lab
• test subjects
• cold
• thermostat

The young couple vanished after going swimming in the waters near the Salton Sea where the molluscs were present. Navy divers later discovered a giant mollusc and a large egg on the ocean floor along with one of the victims' bodies, confirming the couple's fatal encounter with the creatures.

• couple
• swimming
• disappear
• diver
• mollusc
• victim

The Navy divers systematically searched the irrigation canal system and located a cluster of molluscs gathered together. They deployed explosives to destroy the creatures and halt their spread toward populated areas.

• navy divers
• canals
• explosives
• destroy
• molluscs
• cluster