About the Book: In this thrilling Greek mythology adventure, demigods Nico di Angelo and Will Solace return to Camp Jupiter to help Hazel Levesque deal with a growing crisis among reformed Underworld monsters. After offering monsters a chance at redemption in The Sun and the Star, a dark force now threatens to destroy them, one by one. As Nico, Will, and Hazel uncover a haunting connection to the danger, they must confront their pasts and protect a fragile peace between gods, monsters, and demigods.