Twenty years after the Giant War, there is finally peace between the Roman and Greek camps. The threat of Gaia is gone, and the legendary Percy Jackson's prophecies have nearly become myths. Everything is of the past...until now. Ancient beings as old as Gaia herself are stirring, certain to settle a dispute that is happened back in the 1930's that may yet destroy the world. Sebastian Jackson is used to being regarded as a celebrity just because of his famous father, Percy Jackson. However, he knows all the glory truly belongs to his dad alone. The hardest quest he's ever been on is the lifetime task of keeping his younger brother Luke out of trouble. But while on a field trip in Tartarus, he stumbles upon a never-before-explored part of the abyss that holds a very deadly secret as older than time. Can even the son of Percy Jackson save the world from beings so powerful, they are the essence of time and space itself?