The Heroes of Olympus, Book four The House of Hades

At the conclusion of The Mark of Athena Annabeth and Percy tumble into a pit leading straight to the Underworld The other five demigods have to put aside their grief and follow Percy s instructions to find the mortal side of the Doors of Death If they can fight their way through Gaea s forces and Percy and Annabeth can survive the House of Hades then the Seven will be able to seal the Doors from both sides and prevent the giants from raising Gaea But Leo wonders if the Doors are sealed how will Percy and Annabeth be able to escape They have no choice If the demigods don t succeed Gaea s armies will never die They have no time In about a month the Romans will march on Camp Half Blood The stakes are higher than ever in this adventure that dives into the depths of Tartarus This paperback edition will include a new short story in which Percy and Annabeth fight alongside Carter and Sadie Kane