A true-life drama in the 1920s, centering on British explorer Col. Percy Fawcett, who discovered evidence of a previously unknown, advanced civilization in the Amazon and disappeared whilst searching for it.

Island of La Réunion, in the beginning of the 20th century. Five teenagers commit a savage crime. As punishment, a Dutch captain takes them to a supernatural island with luxuriant vegetation and bewitching powers.

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 sister 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.