In San Francisco, well-known sportsman Kay Hoog announces to a club that he has found a message in a bottle with a map drawn by a Harvard professor who has gone missing. The map tells of a lost Incan civilization that possesses an immense treasure. Hoog immediately plans an expedition to find it. But Lio Sha, the head of a criminal organization known as the Spiders, is determined to get the treasure for herself and plans a rival expedition.