Corporal Larry Grant and Sergeant "Mac" McGowan, of the United States Marine Corps, are rival for the love of Frances Schiller, but team up to hunt down "The Tiger Shark," a mad, scientific wizard who is holding Sergeant William Schiller, Frances' brother, a prisoner on a wild, jungle island in the Pacific.
| Actor | Role |
|---|---|
 Grant WithersCpl. Larry Lawrernce | Cpl. Larry Lawrernce |
 Adrian MorrisSgt. Mack McGowan | Sgt. Mack McGowan |
 Ann RutherfordFrances Schiller | Frances Schiller |
 Robert WarwickCol. W. R. Bennett | Col. W. R. Bennett |
 George J. LewisSgt. William Schiller [Chs. 1-4] | Sgt. William Schiller [Chs. 1-4] |
 Pat O'MalleyCapt. Grayson [Ch. 1] | Capt. Grayson [Ch. 1] |
 Victor PotelFake Native Chief [Ch. 12] | Fake Native Chief [Ch. 12] |
 Jason Robards Sr.Kota | Kota |
 Warner RichmondMetcalf | Metcalf |
 Robert FrazerH.R. Douglas | H.R. Douglas |
 J. Frank GlendonM.J. Buchanan | M.J. Buchanan |
 Donald ReedPedro | Pedro |
 Max WagnerGibson | Gibson |
 Richard AlexanderIvan | Ivan |
 Tom LondonMiller | Miller |
 Jim CoreyKarlsson | Karlsson |