Commander George M. Dyott (real life adventurer who wrote the non-fiction book the movie is based on) organizes an expedition to find out what happened to an earlier expedition which has vanished in the Brazilian interior, while searching for the lost city of gold, El Dorado. With several other white men and local natives, the searchers travel by mule, canoe and foot, while battling man-eating piranhas, rapids, nature and hostile Indians. They reach an area where the natives offer proof the expedition was there, but Dyott is convinced that they killed the earlier-expedition members and the local chief has the same plans for his group.
—Les Adams <longhorn1939@suddenlink.net>