This has been one of my most favorite books out the series. I like how the story ended and left open the possibility for even more to come. I think my biggest surprise was seeing that Rachel Dare became the Oracle for the Camp at the end. I also felt sorry for Nico in the beginning. He was trying to not only help Percy but in the process had betrayed him as well by bringing him to his father, Hades. I even felt more sorry for the boy upon learning the sad truth behind the reason why he and Bianca had been placed in the Lotus Hotel and kept there. Still this book was wonderful and enjoyed. I hope I can lure my sister into reading it now.