The Beast from 20,000 Fathoms

A nuclear bomb test called Operation Experiment is detonated far north of the Arctic Circle. Physicist Thomas Nesbitt muses about the cumulative effects of all atomic tests, a question that lingers as events unfold.

The explosion unfreezes a 200-foot carnivorous dinosaur, the Rhedosaurus, from millions of years of suspended animation. Nesbitt is the only witness to the awakening and is later dismissed as delirious when recounting what he saw. The beast begins a slow, terrifying movement toward the surface world.

Nesbitt encounters skepticism from authorities who doubt his account of the awakening. He persists in documenting sightings, convinced that the creature exists and is moving toward populated areas. The disbelief heightens the tension between eyewitness testimony and institutional decision-making.

The Rhedosaurus travels down the East Coast, sinking a fishing ketch off the Grand Banks and wrecking structures along the way. It also destroys a lighthouse in Maine and damages buildings in Massachusetts as panic rises among coastal communities. Nesbitt's mapping of sightings helps track its path.

After a surviving fisherman identifies from drawings the very same dinosaur Nesbitt described, he connects with paleontologist Thurgood Elson and his assistant Lee Hunter. The trio begins to coordinate sightings on a map and shares notes about the creature’s behavior. Their partnership marks a turning point in countering the threat.

Elson hypothesizes that the Rhedosaurus is heading toward the Hudson River region. He uses a mapped account of sightings to argue for a location-based search. The plan shifts from a general chase to a targeted hunt.

Elson suits up for a diving bell expedition into the Hudson River Canyon to locate the beast. The creature ambushes the bell and swallows it, killing Elson in the process. The loss of Elson leaves the team in disarray, but the monster continues toward Manhattan.

After the underwater encounter, the beast emerges and roams through Manhattan. It devours a police officer and tears through cars and buildings, triggering a citywide panic. News reports tally the devastation with high casualty figures.

Colonel Jack Evans leads troops who set up an electrified barricade to stop the creature, then attempt a direct strike with a bazooka aimed at the throat. The plan drives the beast back into the sea, but it bleeds on the streets, spreading a dangerous contagion. The contagion complicates efforts to incinerate or explode the monster.

The bleeding from the wound releases a prehistoric contagion that threatens to spread through the city. Officials realize conventional methods to kill or burn the Rhedosaurus could spread the infection further. The plan shifts toward containment and neutralization of the infection.

A radioactive isotope is prepared to be injected into the beast's neck wound to burn it from within while halting the contagion. The dual goal is to kill the creature and prevent further infection spread. It marks a desperate, life-saving gamble.

Corporal Stone and Nesbitt ride the Coney Island Cyclone roller coaster to reach the beast at eye level. Stone fires the isotope-laden grenade into the beast's neck wound as the coaster tops the tracks. Sparks fly, the park catches fire, and panic intensifies.

The roller coaster becomes a conduit of sparks as the isotope takes effect and the amusement park erupts in flames. The Rhedosaurus writhes under the radiation and finally collapses. The contagion is neutralized as the creature dies.

With the creature dead, the city begins counting the cost of the disaster while recovery operations commence. Nesbitt reflects on the dangers of nuclear testing and the unpredictable consequences. The tale ends with a cautionary note about humanity s reach for power.