|Directed by||Charles B. Griffith|
|Produced by||Charles B. Griffith|
|Written by||Charles B. Griffith|
|Edited by||Jerome Thoms|
|Distributed by||Columbia Pictures|
|Running time||66 mins|
A freelance frogman (Jon Hall) is hired by a psychotic treasure hunter to recover an emerald that went down in a shipwreck.
- Jon Hall as Dave Courtney
- Nan Adams as Joanne Godfrey
- John Farrow as Edward Stuart Godfrey
- Jonathan Haze as Jack Mautner
- Greigh Phillips as Dean Pike
- Dave "Howdy" Peters as Fermin Fry
- Tookie Evans as Raul Estoril
- Martin Denny as Marty
- Bob La Varre as Cal Priest
Griffith had signed with Columbia under a five-film writer-producer-director contract; he ended up only making two of them, the other being Ghost of the China Sea, which he did not direct.
"They were really terrible," he recalled later. "It stopped me for twenty years from ever directing again. They were really rank. You see, I got chicken and started to write very safely within a formula to please the major studios, and of course, you can't do that."
"I had an early chance to direct but was too dumb to know that I had to work with the editor," Griffith said later. "They told me I had an Oscar-winning editor; I told them we needed an Oscar-winning firestarter."
- Aaron W. Graham, 'Little Shop of Genres: An interview with Charles B. Griffith', Senses of Cinema, 15 April 2005 retrieved 22 June 2012
- Dennis Fischer, 'Charles B. Griffith: Not of this Earth', McGilligan, Patrick. Ed Backstory 3: Interviews with Screenwriters of the 60s Berkeley: University of California Press, c1997 1997 retrieved 22 June 2012
- Pierre Perrone, 'Obituary - Charles B. Griffith Screenwriter of the cult classic 'The Little Shop of Horrors' ', The Independent 8 October 2007 accessed 26 June 2012
- 'MOVIELAND EVENTS: NAN ADAMS WILL DO LEAD WITH JON HALL', Los Angeles Times (1923-Current File) [Los Angeles, Calif] 24 Sep 1957: 23.
- Forbidden Island at IMDB
- Forbidden Island at TCMDB
- Forbidden Island Movie Poster
- Forbidden Island in ʻColumbia Pictures Horrorʻ by Michael R. Pitts at Google Books