When a native policeman is seriously injured by a diamond thief, Tarzan tries to get the criminal to jail - and keep the officer's angry tribe from taking the law into its own hands.

A airplane crash in the jungle results in Tarzan racing to save a girl's life and a perilous struggle with a convicted criminal.

Tarzan becomes concerned when news reaches him of plans to build a dam in a geologically unsound area. He needs to prove the weakness in the plan and why none of the government surveys in the area have not uncovered the same issues.