Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: Uncomfortable but well written mystery

I agree with other reviewers that this is the darkest and most chilling installment in the series so far. It's not the sort of topic I choose to read about and I, too, noticed the relative lack of engagement with the natural park setting that drew me to this series in the first place. Neither is there much in terms of further developing the Anna Pigeon character. But that said, as far as a mystery story goes, this one was well done--enough so to give me a nightmare.