On a trip with his dad after a freak storm hits their boat, Darrel McLeod wake up to find not only is his father missing but he's in some type of hollow earth with all kinds of prehistoric life. On his search for his dad he'll encounter many prehistoric animals and stone age people. He'll also not only have to find his dad but help save his friends from a very tyrannical group.

This is not strictly Tarzan per se, but it's basically the same thing with the names changed. A wealthy young lady encounters a wild man in the deadly jungle.

The true story of Jane Porter, a young zoologist who travels with her father to deep Africa to catalog new species. She discovers wild man Tarzan who reveals Africa's secrets, including the lioness in her heart. Caught between greedy British Marines, a vicious native tribe, and her own desire, Jane must choose between her dedication to science and the yearnings in her soul.