On a volcanic island near the kingdom of Hetvia rules Count Dakkar, a benevolent leader and scientist who has eliminated class distinction among the island's inhabitants. Dakkar, his daughter Sonia and her fiance, engineer Nicolai Roget have designed a submarine which Roget pilots on its initial voyage just before the island is overrun by Baron Falon, despotic ruler of Hetvia. Falon sets out after Roget in a second submarine and the two craft, diving to the ocean's floor, discover a strange land populated by dragons, giant squid and an eerie undiscovered humanoid race.
- Original title: The Mysterious Island
- Release date: Oct. 5, 1929
- Status: Released
- Genres: Adventure, Science Fiction, Romance
- Runtime: 1h 35min
- Producers: Metro-Goldwyn-Mayer