Kronos's forces have found a way into Camp Half-Blood through Daedalus's Labyrinth, the impossible maze that runs beneath the surface of America. Percy and his friends enter it to find Daedalus and close the passage before the Titan army uses it. The penultimate book of the original series, darker and more morally complex than its predecessors, with the best Riordan has written about loyalty and betrayal.
