About the book: year / Nancy and her friends, Georgie and Bess, returning from a village carnival, witness an explosion and fire in a beautiful estate. Fearing for its inhabitants, who might be left behind in the burning building, they rush to the rescue - and are suddenly faced with a mystery that seems insoluble. The first clue to the solution was an anonymous diary, but the entries in it were written in such hard-to-read handwriting that it was difficult to decipher. The technical drawings and chemical formulas on its pages look even more amazing. Who dropped the diary near a burning house? Was it the thin stranger whom Nancy had glimpsed as he ran away from the burning house? What was he doing there? And does he know where Felix Raybolt is, the crooked patent attorney who hasn't been seen since his house burned down? Or maybe Raybolt died in the fire? Firefighters believe that the devastating explosion and subsequent fire may not have been an accident - someone could have taken revenge on the owner. All the evidence points to Joe Swenson, an inventor who was duped by Sly Felix. Having befriended Mr. Swanson's five-year-old daughter, Honey, the young detective makes desperate efforts to clear the inventor of arson suspicions. Another exciting book about Nancy Drew will tell you about this..