This series could've easily been 11 books to be honest. Books 11 and 12 were filler books in my opinion and a bit on the boring side but I still enjoyed them because I love the characters so much. I'm really glad I got the audio books for 11 and 12, it made reading them a whole lot better and fun. There were some more mysteries thrown in in book 12 and a bunch of characters from previous books make a return which was fun. I hope 13 wraps all of this up. I'm going to miss these characters and world when it's all over. 
 - Richard :)