While walking through the jungle Tarzan discovers a large whale with a harness strapped to him. Tarzan discovers that the whales are being used to create power for the City of Atlantis. The whale takes Tarzan to Atlantis which is deep under the water to investigate. Tarzan learns that the only way to keep the city from becoming flooded is to keep generating power. Tarzan helps discover an alternate power source so that the animals can be freed and the city can be saved.