A professor and his colleagues follow an explorer's trail down an extinct Icelandic volcano to the Earth's centre. However, they face many challenges in their quest.
After the death of Cyrus, his attorney Corby invites his relatives and Joyce Norman is declared as the sole beneficiary. Cyrus has drafted a second will that puts Joyce's life in danger.
When his cattle begin to mysteriously disappear, rancher Jimmy Ryan looks for answers. He is soon horrified to learn that a giant dinosaur hiding in Hollow Mountain is eating his livestock.