When demonic cheerleaders invade his high school, Percy Jackson hurries to Camp Half Blood, from whence he and his demigod friends set out on a quest through the Labyrinth, while the war between the Olympians and the evil Titan lord Kronos draws near.

A new prophecy leads to a dangerous quest. When Percy receives an urgent distress call from Grover, he immediately prepares for battle. He knows he'll need his powerful demigod allies, Annabeth and Thalia, at his side; his trusty bronze sword, Riptide; and...a ride from his mom. The demigods race to the rescue, only to find that Grover has made an important discovery: two new powerful half-bloods, whose parentage is unknown. But that's not all that...