On a yacht south of the Equator waters, we meet a ruthless tycoon named Thornton Armitage and his family whose daughter's wed to the arrogant Ned Hallet along the trip is a paleontologist Steve who's teaching Thornton's son Billy about dinosaurs. During the voyage, Steve becomes attracted to Thornton's daughter Elaine and they both start to fall in love but all are disrupted by a large typhoon that threatens the yacht and begins to sink evacuating to a nearby submarine the group then finds themselves in a prehistoric land filled with dinosaurs, prehistoric beasts, and exploding volcanoes. Steve decides since he is the dinosaur expert to lead the group through survival but Hallet who is a trigger-happy hunter is jealous of Steve upon leaving the group he hunts down a baby Triceratops and meets his demise at the hand of an angry mother. After encountering many reptilian creatures of this lost world the group must make contact with the outside world before the prehistoric wonder around them is lost to the deadly forces of nature.
