Demigods Nico di Angelo and Will Solace must endure the terrors of Tartarus to rescue an old friend in this thrilling adventure co-written by New York Times #1 best-selling author Rick Riordan and award-winning author Mark Oshiro. Percy Jackson fans, rejoice! Nico and Will have a book of their own! As the son of Hades, Nico di Angelo has been through so much, from the premature deaths of his mother and sister, to being outed against his will, to losing his friend Jason during the trials of Apollo. But there is a ray of sunshine in his life—literally: his boyfriend, Will Solace, the son of Apollo. Together the two demigods can overcome any obstacle or foe. At least, that's been the case so far . . . Now Nico is being plagued by a voice calling out to him from Tartarus, the lowest part of the Underworld. He thinks he knows who it is: a reformed Titan named Bob whom Percy and Annabeth had to leave behind when they escaped Hades's realm. Nico's dreams and Rachel Dare's latest...