In the Fabulous Thirties, Doc Savage and his five Amazing Adventurers are sucked into the mystery of Doc's father disappearing in the wilds of South America. The maniacal Captain Seas tries to thwart them at every turn as they travel to the country of Hidalgo to investigate Doc's father's death and uncover a vast horde of Incan gold.

Mrs. Anna Leonowens and her son Louis arrive in Bangkok, where she has been contracted to teach English to the children of the royal household. She threatens to leave when the house she had been promised is not available, but falls in love with the children. A new slave, a gift of a vassal king, translates "Uncle Tom's Cabin" into a Siamese ballet. After expressing her unhappiness at being with the King, the slave decides to make an attempt to escape with her lover. Anna and the King start to fall in love, but her headstrong upbringing inhibits her from joining his harem. She is just about to leave Siam but something important she finds out makes her think about changing her mind.