The book was good. As always there was a nice flow and just enough action. Many of the characters really seemed to come into their own. Frank gained some confidence which also seemed to give him a beefier body. Leo explored his softer side. Nico was able to admit to himself who he really loves and why he's been so distant. I think this is a huge step as far as the Olympian books go. Jason's acceptance of Nico and his admission showed that if Nico was willing to let people in they would indeed be there to support him. Percy and Annabeth journey through Tartarus with Bob. I thought Bob was a great character and I really liked getting to know who he had become. I also think it was good to see Percy's feelings towards Bob and the affect his actions had on Bob's new life. I like that he changed for the better and he liked who he became. 
 What I didn't like about the book was that some parts did seem a bit drawn out and unnecessary. I found myself wanting to rush it along. The part with Cupid seemed a little drawn. It was very necessary and relevant but also repetitive. Same with the part about the Arai. I know it was meant to be a battle between Percy and them that went on and on causing endless pain and curses but I felt it went on a little to long. 
 Overall I enjoyed this book but I was definitely let down that there was not more closure at the end. I guess I should have known there was another book coming being that this is only #4.