Screenplay written by Ib Melchior and Ed Watson
Investigating the region of the active Noshiro volcano in Japan, American scientist Dr. Roy Carlyle and his assistant Marge discover a vast cavern containing the preserved bodies of a tyrannosaurus rex and an ankylosaurus, creatures apparently claimed by the lava aeons ago while locked in mortal combat, then preserved by the volcanic gases. Ignoring the warnings of their Japanese colleagues not to disturb the creatures, believing them to be the legendary 'Monsters of Noshiro'. The warning is passed off as superstitious prattle and Dr Carlyle arranged for the US Navy to excavate the cavern and transport the two beast to San Francisco for study at a special facility. During the ocean voyage, a love triangle begins to emerge between Marge, palaeontologist Corvin and Navy Commander Steve McBain.
It is discovered during the voyage that far from being dead, the two immense reptiles are in a state of hibernation. The news increases the concerns of Carlyle and Corvin for their specimens, but Commander McBain, thinking in terms of threat assessment, would like nothing better than to dump both creatures overboard. During a violent storm, he gets part of his wish fulfilled. One of the cables supporting the tyrannosaurus breaks, having been loosened by Corvin out of fear of damaging the dinosaur. The huge reptile slips overboard, sinking into the ocean.
The ship, now minus one dinosaur, arrives in San Francisco. While Commander McBain and Marge enjoy their first night ashore in one another's company, strange events unfold out in the bay. Far from having drowned, the tyrannosaurus has survived and awakened from its slumber, following the ship to San Francisco. Sensing its ancient enemy, the ankylosaurus also awakens and quickly escapes from its own cables. The monsters do battle along the shore, crushing power houses and blacking out parts of the city. As a consequence of their fight, an entire oil refinery is set ablaze, causing both dinosaurs to retreat into Chinatown.
News of the horrible carnage causes Carlyle to suffer a stroke, horrified by the death and destruction he's brought to the city. Carlyle begs McBain to destroy the monsters, but his physician warns that if the monsters are destroyed then Carlyle will not receive the acclaim of the scientific community and the resulting depression may very well kill him. Meanwhile, half of the problem resolves itself when the tyrannosaurus kills its enemy, leaving the army with only one monster to deal with.
At the university, Marge and a team of scientists desperately work on a formula to recreate the Noshiro volcanic gas and place the remaining dinosaur back into hibernation. They continue to work even as the dinosaur approaches the building, forcing McBain to dash in and rescue Marge before the tyrannosaurus can destroy the structure. Having destroyed the scientists, the tyrannosaurus heads back to sea, pursued by the Navy. The pursuit of the tyrannosaurus leads to the Arctic Circle, where it is deduced that the dinosaur intends to lay its eggs. Faced with this news, McBain ponders the use of the atomic bomb to prevent the tyrannosaurus from producing even more monsters. However, he decides on another plan that might stop the monster without destroying it. The Navy rings an ice canyon with oil drums, hoping to seal the monster within a ring of fire. McBain narrowly escapes as the tyrannosaurus lumbers toward the barrels, igniting them with a grenade. Jets bombard the sides of the canyon with missiles, causing an avalanche of ice and snow, completely burying the dinosaur. The cold temperatures will force the tyrannosaurus back into a state of hibernation - a state in which Carlyle and other scientists will be able to safely study it.
However, back at the Noshiro volcano, something stirs within the cavern.
History:
Film producers Harold Ross and Edward Barison intended to employ Toho's 'Godzilla Raids Again' as the skeleton for a 'new picture'. Having experienced a tremendous profit from re-crafting Toho's first 'Godzilla' into Godzilla, King of the Monsters by the expedient of rearranging scenes and inserting new footage with American actor Raymond Burr, the notion of doing an even larger amount of original footage to employ in 'reworking' the second Godzilla picture seemed a natural one. Ross hired screenwriters Ib Melchior and Ed Watson to create a new screenplay based around the Japanese effects footage they would be keeping. The result was 'The Volcano Monsters'.
Although the project went far enough ahead that Toho even sent Godzilla and Anguirus costumes to Hollywood for use in fabricating new effects shots for 'The Volcano Monsters'. However, AB-PT Pictures Corporation, which were to produce and distribute the film, folded before the project advanced further. Warner Brothers would eventually buy the rights to 'Godzilla Raids Again', deciding to simply dub the film rather than shoot any new footage, releasing it as Gigantis the Fire Monster in 1959.
