Clue of the Black Keys - Couverture rigide

Terry Scott, a young archaeology professor, seeks Nancy’s help in unearthing a secret of antiquity which can only be unlocked by three black keys. While on an archaeological expedition in Mexico, Terry and Dr. Joshua Pitt came across a clue to buried treasure. The clue was a cipher carved on a stone tablet. Before the professor had time to translate the cipher, the tablet disappeared – along with Dr. Pitt! Terry tells Nancy of his suspicions of the Tinos, a Mexican couple posing as scientists who vanished the same night as Dr. Pitt. Nancy and her friends follow a tangled trail of clues that lead to the Florida Keys and finally to Mexico in this suspense-filled story that will thrill readers.

Carolyn Keene is a pen name used by a variety of authors for the classic Nancy Drew Mystery series. The first author to use the pseudonym was Mildred Wirt Benson, who wrote 23 of the original 30 books. Other writers who have adapted the "Carolyn Keene" moniker include Leslie McFarlane, James Duncan Lawrence, Walter Karig, and Nancy Axelrod.