Great Britain

Ben McBride (Patrick Wayne) leads an expedition to the lost island of Caprona to search for his friend Bowen Tyler (Doug McLure). After their plane is attacked by a Pterodactyl, they set off through the strange country on foot. A beautiful native girl Ajor (Dana Gillespie) tells them Tyler has been captured by the Na-Gas, a savage tribe who sacrifice prisoners to their Volcano God. They in turn are captured and held prisoner in the City of Skulls, built entirely from Human Skulls.