The year is 1935. Marion Bailey learns of a 13th century lexicon of Latin, Persian, and Turkish connected to a collection medieval riddles. In a way that confuses British Intelligence, it is somehow connected to modern day and a British opeartion dealing with petroleum resources in the Caspian region. She is directed by Jeffrey Willcox to investigate. What she learns in her travels to Azerbaijan will threaten not only that area but also possibly bring about a World War.