Nancy drew 28: the clue of the black keys - carolyn keene

Terry Scott, a young archaeology professor, seeks Nancys 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.

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.