I loved this book! As you should recall, it ended on a literal cliffhanger, with Annabeth and Percy falling in to Tartarus, good news: they survive! Part of the book follows their journey to close the Doors of Death. Most of the book follows the other demigods trying to return the Athena Parthenos to Camp Half Blood in time and save their friends. Nico and Reyna also appear! I’m going to say that there was a scene that may surprise people (no spoilers) but don’t let it discourage you from reading the next book, it’s not even part of the main book. Only one chapter. The book is exciting, suspenseful, and told wonderfully! It’s one of my favorite books in the series.