This jungle adventure features an extremely complicated plot that involves a megalomaniacal Nazi doctor who continues to perform inhuman experiments in the Amazon jungle and helms the Lost City of the Nazis, a mecca for war criminals and new followers. He is pursued by three vengeful people: a former colleague whom he double-crossed near the end of the war, a young woman who saw him murder her father, and an angry American physician, whose daughter the doctor kidnapped after they came to the jungle to help the ailing Indians who are dying from a mysterious disease. In addition to coping with each other, the searchers must also deal with the usual Amazon dangers, including ferocious cannibals, before they can make it to the hidden city and get their revenge. The plot is an adaptation of an Alistair McLean novel.