The House of Hades (the Heroes of Olympus, Book Four (New Cover), Paperback

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. The accessible and dramatic cover art by graphic novelist Nilah Magruder will attract a new generation of fans.

Rick Riordan, dubbed "storyteller of the gods" by Publishers Weekly, is the author of five #1 New York Times best-selling middle grade series with millions of copies sold throughout the world: Percy Jackson and the Olympians, The Heroes of Olympus, and the Trials of Apollo, based on Greek and Roman mythology; the Kane Chronicles, based on Ancient Egyptian mythology; and Magnus Chase and the Gods of Asgard, based on Norse mythology. Rick collaborated with illustrator John Rocco on two #1 New York Times best-selling collections of Greek myths for the whole family: Percy Jackson's Greek Gods and Percy Jackson's Greek Heroes. Rick is also the publisher of an imprint at Disney-Hyperion, Rick Riordan Presents, dedicated to finding other authors of highly entertaining fiction based on world cultures and mythologies. He lives in Boston, Massachusetts with his wife and two sons. Follow him on Twitter at @camphalfblood.

Nilah Magruder is a writer and artist based in Los Angeles, California. From her early days she developed an eternal love for three things: nature, books, and animation. She has written and storyboarded for studios such as Disney and DreamWorks. She also illustrates children's books, including the Dactyl Hill Squad series by Daniel Jose Older. Nilah is the author-illustrator of M.L.K., a middle grade graphic novel that won the Dwayne McDuffie Award for Diversity, and How to Find a Fox, a picture book. She has published short fiction in the anthology All Out, in Fireside magazine, and for Marvel Comics. When she's not working, Nilah is watching movies, growing herbs, roller-skating, and fighting her cat for control of her desk chair. Follow her on Twitter at @nilaffle.