When Percy Jackson receives an urgent distress call from his friend 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 to find that the Titan Lord Kronos has set up his most devious trap yet and that the young heroes have just fallen prey. When the goddess Artemis goes missing, she is believed to have been kidnapped. And now it's up to Percy and his friends to find out what happened. Who is powerful enough to kidnap a goddess? They must find Artemis before the winter solstice, when her influence on the Olympian Council could swing an important vote on the war with the titans. Not only that, but first Percy will have to solve the mystery of a rare monster that Artemis was hunting when she disappeared--a monster rumored to be so powerful it could destroy Olympus forever.