 During World War II, David Simms pilots supplies between India and China over the Himalaya Mountains. One day he s forced to miss a flight and is replaced by his friend, Bill March. March s plane is lost en route and Simms feels guilty. Back in America he meets March s widow, Elaine. They marry and then both travel to Tibet to learn more about March s fate and about a mysterious Tibetan mask which has come into their possession.