Victoriana Haden and Callum Bishop set out on a quest to gather more information regarding the Oracle of Delphi's prophecy. Cal's past is mysterious. After his father's true identity was revealed by Vic, and confirmed at the Apple Harvest Festival, he's searching for answers. Is he a Halver-half-mortal and half-immortal-as Vic suspects? Or is he something else altogether? His past ends up more complicated than he ever could have suspected. Vic will do anything to help Cal find the answers he seeks, including a trip to the cryptic Fates Sisters. But something is amiss. And the line between the Above World and Below World seems to be seeping energy. Naturally, treachery always seems to follow the Princess of the Under World, and she soon finds herself kidnapped along with her hellhound childhood friend and ex-boyfriend, Asher. Will Cal be able to save Vic in time? Will Pythia's prophecy about the House of Snakes come to fruition? When you're the daughter of Hades nothing ever comes easy.