Unlike any other mystery series I have read, this one very much assumed the reader was familiar with all of the main character's previous adventures. More than that, the author seemed to have suddenly learned a great deal about theoretical physics and decided that was going to be crucial to a plot. Said plot was, quite frankly, difficult to suss out, and the ending was so unsatisfying that it almost felt as though Grimes got to the end and was like "well, I'm tapped out."