The Chinese border town of Baskul is occupied by the Japanese. British diplomat Robert Conway, war hero and celebrated writer, man of action and disillusioned idealist, smuggles 90 of his countrymen out to Shanghai. He himself boards a small plane with his brother George, paleontologist Alexander P. Lovett, bankrupt financier Henry Barnard, who is on the run from the police, and Gloria, an American woman with tuberculosis. They fail to notice that the murdered pilot has been replaced by a mysterious Mongolian who is steering the plane on a completely different course. In the mountains of Tibet, the plane makes an emergency landing and the pilot is killed. The five passengers, thousands of kilometers away from civilization, are doomed to certain death, but a caravan of lamas miraculously comes to their aid and takes them to the city of Shangri-La, located in the Valley of the Blue Moon, a paradise lost in the mountains of…