Upon saving Zupisa the great whale who had been beached, Tarzan discovers that Lord Cinnabar of Atlantis had enslaved the whales and uses them to power it while King Neptune is away.
While hiding out in a cave during a thunderstorm, Tarzan and N'kima come to the aid of Layir of the Bird People who had injured his wing. Tarzan soon learns that the Bird People have been in a feud with the local "Land People."
Tarzan rescues a miniature woman named Reba and brings her home to the Isle of Zerus where he tries to bring peace between the advanced cities of Onada and Zome. But to do that he must defeat the giant robot Colossus built by the Zomans.
The evil twin of the Wazdon Chief Denat has assumed his identity and has been having the tribesmen mine for gold in a volcano. It is up to Tarzan to stop him.
Tarzan and N'kima find a group of Conquistadors in the jungle where their leader Carlos claims that the treasure of his ancestors are in the mountains where the Donlumangani live.
