In this Nancy Drew mystery, Nancy and her friend Helen are staying at Lilac Inn, a hotel owned by their friend Emily Willoughby. Nancy discovers she has an imposter posing as her when her house is robbed and a store calls her claiming she bought some items but did not pay. Later, Emily is presented with her inheritance- twenty valuable diamonds- at the inn for her birthday. The power mysteriously goes and out and when they come back on, the diamonds are missing! Further events make Nancy suspect the jewel theft and her imposter are connected. Being the excellent detective she is, Nancy eventually gets to the bottom of it. I really enjoyed this book. It was a good mystery. Some aspects of the book (such as a typewriter being mentioned) are a little outdated but those were minor details. I have not read the other three Nancy Drew mysteries in this series, but there were no references to events in those books that confused me. Overall I really liked this book, and I recommend it to all fans of Nancy Drew or mystery novels. The next book after this is The Secret of Shadow Ranch.