This started out as such a fun and engaging series, but the last two or three books have been really weak, and this is little better.  It wraps everything up all nicely and neatly, but is not much fun to read along the way.  It's an easy read, though, so if you're looking to kill some time, by all means.  I'm disappointed. 

Question: What is the central idea of ​​the book?
Answer: This started out as such a fun and engaging