After learning that he is the son of a mortal woman and Poseidon, god of the sea, twelve-year-old Percy is sent to a summer camp for demigods like himself, and joins his new friends on a quest to prevent a war between the gods

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...

All year the half-bloods have been preparing for battle against the Titans, knowing the odds of a victory are grim. Kronos's army is stronger than ever, and with every god and half-blood he recruits, the evil Titan's power only grows. While the Olympians struggle to contain the rampaging monster Typhon, Kronos begins his advance on New York City, where Mount Olympus stands virtually unguarded. Now it's up to Percy Jackson and an army of young demigods...