What a mystery. A widow works incognito as a piano teacher to solve the mystery of her sister's disappearance. The title may give it away, but throughout the book, the reader is given many chances to figure out who, how, and why before it is actually revealed. There is an eerie "haunted" mansion, lots of shocking secrets, desire, and many disturbing encounters. This was a perfect introduction to Victoria Holt. Read it, you'll like it.