All year long, the demigods prepared for the battle against the Titans, knowing that the chances of victory were very small. Kronos's army is stronger than ever, and with every god and half-blood he recruits, the power of the evil Titan only grows. While the Olympians struggle to contain the rampaging monster Typhon, Kronos begins advancing on New York, where Mount Olympus is completely unguarded. Now it's up to Percy Jackson and an army of young demigods to stop the God of Time. In this important final book, the long-awaited prophecy of Percy's sixteenth birthday is revealed. And as the battle for Western Civilization rages on the streets of Manhattan, Percy faces the terrifying suspicion that he may be fighting against his own destiny.