What is a summary of The Lightning Thief chapter 21?

In chapter 21 of *The Lightning Thief*, titled "The Oracle," Percy and Annabeth arrive at the Oracle of Delphi, a mystical woman who provides cryptic prophecies. Percy is anxious and scared because the Oracle's predictions are often dire. He wants to know about his father and the prophecy about the "son of the Big Three" who will either save or destroy the world.

The Oracle's prophecy is disturbing:

* "The boy shall face the three trials, the first against the son of Poseidon. The second against the daughter of Athena. The third against the son of Hades."

* "The boy shall fight the Titan's curse, the boy shall face the fury of the gods."

The prophecy is shrouded in mystery and doesn't reveal much about the trials or the true nature of the threat. The Oracle also tells Percy that he must choose between two paths: "He will face his destiny or he will face death."

Annabeth, ever the strategist, reminds Percy that they have to find Luke. She believes that he is the key to figuring out the prophecy and the next steps they need to take.

The chapter concludes with Percy feeling overwhelmed and confused. He is unsure how to interpret the prophecy, but he knows he has to face his destiny, whatever it may be.