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 is inescapable.

A Children’s Bookshelf Selection: Each month our editor’s pick the best books for children and young adults by age to be a part of the children’s bookshelf. These are editorial recommendations made by our team of experts. Our monthly reading list includes a mix of bestsellers and top new releases and evergreen books that will help enhance a child’s reading life.