Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Starts great but quickly goes downhill

Christopher Fowler has an atmospheric setting and a nifty plot to hang his story on but that can't last for three hundred pages. The characters are undeveloped to the point of being annoying. Scenes seem to be writing in such a rush that everything melts together. And of course we get the standard police-trying-to-solve-a-mystery subplot.