The Secret of Red Gate Farm (Nancy Drew Mystery Stories, No 6)

Nancy and her friends, Bess and George, meet Joanne Byrd on a train ride home. Joanne lives at Red Gate Farm with her grandmother, but if they do not raise enough money to pay the mortgage, they will soon lose the farm! Nancy, Bess, and George decide to stay at Red Gate for a week as paying customers. Soon, they learn about the strange group of people who rent a cave on the property. They describe themselves as a nature cult called the Black Snake Colony. Nancy investigates their group and helps to uncover a ring of counterfeiters in town!

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.