The stakes have never been higher. If Percy Jackson and Annabeth fail in their quest, there'll be hell on Earth. Literally.Wandering the deadly realm of Tartarus, every step leads them further into danger. And, if by some miracle they do make it to the Doors of Death, there's a legion of bloodthirsty monsters waiting for them.Meanwhile, Hazel and the crew of the Argo II have a choice: to stop a war or save their friends. Whichever road they take one thing is certain - in the Underworld, evil ...

Though the Greek and Roman crew members of the Argo II have made progress in their many quests, they still seem no closer to defeating the earth mother, Gaea. Her giants have risen - all of them - and they're stronger than ever. The gods, still suffering from multiple personality disorder, are useless. How can a handful of young demigods hope to persevere against Gaea's army of powerful giants? As dangerous as it is to head to Athens, they have no other option. They have sacrificed too much a...