When an ancient artifact and a little boy go missing, Nancy and her friends are on the case. The artifact may prove that the Chinese discovered America prior to Columbus, but someone doesn't want that knowledge public and is out to stop Nancy, permanently

Nancy and friends investigate the disappearance of an eccentric woman's chimpanzee and the expensive diamond necklace he was wearing

A billionaire environmentalist has constructed bio-domes in River Heights to help save the planet, but, shortly after a gross green substance destroys one of the domes, creatures such as Sasquatch, Okala Kane, and the Abominable Snowman are seen lurking nearby. Nancy, Bess, and George investigate

"As the engine is transported across country by train, Nancy must protect it from sinister forces that will stop at noting to destroy it--and everyone on board!"-- P. [4] of cover

When Nancy shows up at a charity ball wearing the same dress as her rival Deirdre Shannon, Deirdre is furious, but the girl detective soon has more to worry about when she is kidnapped and must depend on Bess, George, and Ned to rescue her

After stealing a million in investment cash, a desperate robber commandeers a hot air balloon at the local exposition, only to be lost in a raging storm. The balloon was tracked to a high mountain area before going down. When Police Chief McGinnis refuses to take Nancy on the recovery effort, she and the girls stowaway with the investment bankers, also climbing the mountain, in an effort to recover their funds

"Nancy and her father Carson find themselves in an ancient city long buried below a luxurious estate, the sale of which has brought them to Turkey. Thieves led by a mysterious rich man named Harold Severino search frantically for a priceless artifact somewhere in the city as Nancy and her father are taken prisoner. Severino, who previously attempted to purchase the estate with suspicious motives, has been led to the archeological treasure by none...