This is the fourth book in the Heroes of Olympus series. Now, the seven demigods are split- Percy and Annabeth are in Tartarus and the other five are on the Argo II.
Hazel, Piper, Frank, Jason, and Leo have to continue their quest to find the House of Hades, but they have to hurry. They need to rescue Percy and Annabeth. Percy and Annabeth are in a lot of danger- they are barley managing to survive. All seven have to destroy the Doors of Death before its too late and do the impossible.
This book is the most scary of them all especially in the Percy and Annabeth chapters. After all, they are in a place that is almost impossible to survive. It seems as if they will die a couple of times- at least they are together. Of all the couples in the series, Percy and Annabeth are my favorite. They come across some terrible monsters- ones that seem almost impossible to beat- even their powers seem harder to use down there. I constantly was worried after their safety and their survival. I wasn’t expecting some of the help they got or how Percy still used some of his powers. Some of Annabeth’s skills in the pit were unexpected—-as in things I thought were impossible where they were.
For the other five, the impossible is found in The House of Hades- some of them even found powers they didn’t know they had. Such as Hazel’s power to control the Mist or how Frank somehow summoned an army of ghosts. Piper really got stronger in her charmspeak especially when she had to rescue her friends from Khione.
Each of those books get more and more dangerous. Meaning the monsters and giants got stronger. Plus, some of the new monsters seemed scarier than ones they seven already defeated.