When a neighbor asks Nancy Drew to accompany her to an old uninhabited mansion, a new mystery opens ups, and danger lurks on the second floor. Nancy finds a witch tree symbol that leads her to Pennsylvania Dutch country in pursuit of a cunning and ruthless thief.
The friendly welcome the young detective and her friends receive from the Amish people soon changes to hostility when it is rumored that Nancy is a witch! Superstition helps her adversary in his attempt to get her off his trail, but Nancy does not give up. Persistently she uncovers one clue after another.
Nancy's intelligence and sleuthing ability finally lead to the fascinating solution of this puzzling case.
Bess and George invite Nancy on a trip to New Orleans, to help their relatives solve a mystery. Their uncle wants to restore an old showboat, the River Princess, but no one will go near it! Mysterious occurrences are making everything believe the boat is haunted. Can Nancy uncover the truth?
Gold! There are rumors that long ago a treasure was hidden in a city now buried under the Nevada desert. Nancy and her friends plan to join a dig sponsored by two colleges to hunt for the gold. Before she starts, the young sleuth receives an ancient stone table with petroglyphs on it. With this amazing clue, however, come a threat and danger from a thief who also wants the treasure. One harrowing adventure after another besets Nancy, Bess, George, Ned, Burt, and Dave in 102-degree temperatures as they pursue Nancy's hunches above and below ground. They are assisted by a fine woman and a young geology student, but both are unwilling participants in a strange plot. In the end Nancy and Ned nearly lose their lives, just after she has discovered the priceless hidden treasure of gold.
Nancy is asked to locate a stolen pearl necklace that is unusual and very valuable. She soon learns that strange and dangerous people are responsible for the theft. They harass her at home and intensify it when she and her father go to Japan, until they finally manage to kidnap Nancy and her friend Ned Nickerson when she returns to River Heights.
Through clever sleuthing, Nancy is able to penetrate the rites of an amazing group of pearl worshippers, some of whose members are far from devout, and she uncovers underhanded dealings of certain employees of World Wide Gems, Inc., a tremendous international jewelry company. Readers will love accompanying Nancy, disguised as a Japanese girl, in this adventure in Tokyo.
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!