Determined to uncover the fate of good friend Bowen Tyler (Doug McClure), Major Ben McBride (Patrick Wayne) mounts an expedition retracing Tyler's wayward voyage to the Arctic. The quest takes the incredulous party into the amazing hidden tropical land of Caprona... and they soon learn that the cavemen and dinosaurs dwelling within haven't gotten any more hospitable to strangers. Follow-up fantasy from the writings of Edgar Rice Burroughs co-stars Sarah Douglas, David Prowse, Shane Rimmer. 90 min.