Oracles and prophecies feature prominently in The Hidden Oracle. In Greek mythology, the oracles offered people guidance, insights, and warnings. Oracles were often inspired by the gods and could foretell the future. An oracle typically referred to the priest or priestess speaking the prophecy, such as the Pythia at the Oracle at Delphi. For the demigods in Rick Riordan’s extended universe, the Oracles are extremely important as they provide the heroes crucial clues about their quests. In the absence of prophesizing, the demigods often find themselves at sea, especially when confronted by dark and mysterious forces, such as when campers start disappearing into the woods in The Hidden Oracle. Since the Oracle at the camp has stopped prophesizing, the other campers and Chiron do not have any pointers about where to search for the missing demigods.

At the symbolic level, the silence of the Oracles signifies the fall of Apollo, the god of prophecy and the patron of the Oracle of Delphi. Apollo himself can no longer see the future in his present form. Delphi, Apollo’s most important Oracle, described as the “deepest taproot of a tree” (98), has been captured by Python, the ancient snake-like monster. Python’s seizure of Delphi has “strangled” this taproot, starving off the branches of the trees of prophecy.