Fun. While parts of the book—the villains, heroes, and the like—can be a bit predictable, the author does a great job keeping the mystery age-appropriate, funny, and interesting. And admittedly, there were a few curve balls that were thrown in that I didn't see coming, so that was also enjoyable and kept the story lines engaging. Like that the author breaks the book into two separate, larger stories... and appreciate the cliffhangers at the end of most chapters. Loved the use of inner monologues, asides, and some cheeky humor. Overall a fan of the series and what the author's done in writing fun mysteries for young audiences. Great book!