When a famous young woman disappears suddenly, Nancy Drew is faced with an even more puzzling mystery that involves the theft of a jeweled spider. Once the property of the opera diva, Madame Arachne Onides, the gemstone had supposedly passed into the possession of an unscrupulous millionaire. He hired someone to mount it on a silver cobweb necklace, but the gemstone ornament turns out to be a fake!
What has happened to the real jeweled spider, and who masterminded the theft and blackmailed the missing young woman? As Nancy investigates for answers, she is led to the offshore island estate of the late opera star’s husband whose life is being menaced by the same shadowy figure intent on trapping the young sleuth!