The serial also co-stars Gloria Dea, Leonard Penn, Jack Ingram, Rick Vallin, Nick Stuart, William Fawcett, and Rusty Wescoatt.

King of the Congo was based on the comic book character "Thun'da", created by Frank Frazetta, and published by Magazine Enterprises.

King of the Congo centers around a U.S. Air Force captain and his quest to find missing microfilm containing information vital to the United States government.

He is renamed Thunda, King of the Congo, after he repeatedly rings a temple gong using a large stone mallet, sounding the alarm to an attack by the primitive, all-male Cave Men.

At the serial's conclusion, Thunda (Drum) clears the jungle of America's enemy and is able to reunite, as one tribe, the all-female Rock People and all-male Cave Men.