When a fire hits the home of Nancy's neighbors, Nancy investigates whether Paula, a Dutch foreign exchange student staying with them, is somehow connected.
Nancy Drew is determined to get her friend, Andrea's silver Persian cat back from the kitty-kidnappers. The cat was to be the star of a TV pet food commercial, but now is a pawn in a game of cat and mouse.
Nancy and her friends are invited to the 800-acre Highland Retreat in the Cascade Mountains, but flash fires and unexplained mountainside blasts ruin their pleasure. It seems the legend of an untapped gold mine has brought intruders.
Nancy works undercover at The Arizona House, a hot restaurant, in order to find out who is trying to poison the atmosphere and the food. She suspects the key to the problem may be the famed Dragon's Eye Ruby in a nearby mansion.
Nancy comes to visit her former neighbor, Vera, at White Falls, Mass. While she is there, someone threatens Vera's life and Nancy finds herself investigating a murder that happened fifty years ago to find the answer.