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.
When Nancy and her friends ride deep into the Sawniegunk Forest in search of a flying saucer, they find themselves in the middle of more than one mystery. Wildcats, runaway horses, deadly snakes, and a disappearing Indian keep the sleuths tangled in danger and suspense.
A young detective's attempts to uncover a group of poachers on Crocodile Island in Florida involve her with kidnapping, reptiles, enemy boats, and a sinister racket.
A fiery glowing eye in a museum, the abduction of Ned, the code name Cyclops, and a pilotless helicopter draw Nancy and her friends into a dangerous investigation.