After experiencing a series of dangerous—and frankly, humiliating—trials at Camp Half-Blood, Lester must now leave the relative safety of the demigod training ground and embark on a hair-raising journey across North America. Somewhere in the American Midwest, he and his companions must find the most dangerous Oracle from ancient times: a haunted cave that may hold answers for Apollo in his quest to become a god again—if it doesn't kill him or drive him insane first. Standing in Apollo's way is the second member of the evil Triumvirate, a Roman emperor whose love of bloodshed and spectacle makes even Nero look tame. To survive the encounter, Apollo will need the help of son of Hephaestus Leo Valdez, the now-mortal sorceress Calypso, the bronze dragon Festus, and other unexpected allies—some familiar, some new—from the world of demigods. Come along for what promises to be a harrowing, hilarious, and haiku-filled ride. . . .