Since their mother's death, Carter and Sadie have become near strangers. While Sadie has lived with her grandparents in London, her brother has traveled the world with their father, the brilliant Egyptologist, Dr. Julius Kane. One night, Dr. Kane brings the siblings together for a "research experiment" at the British Museum, where he hopes to set things right for his family. Instead, he unleashes the Egyptian god Set, who banishes him to oblivion...

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?

All year the half-bloods have been preparing for battle against the Titans, knowing the odds of 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...

Carter and Sadie, offspring of the brilliant Egyptologist Dr. Julius Kane, embark on a worldwide search for the Book of Ra, but the House of Life and the gods of chaos are determined to stop them.

Despite their best efforts, Carter and Sade Kane can't seem to keep Apophis, the chaos snake, down. Their only hope: find an ancient spell that might turn the serpent's own shadow into a weapon.

Magic, monsters, and mayhem abound when Percy Jackson and Annabeth Chase meet Carter and Sadie Kane for the first time. Weird creatures are appearing in unexpected places, and the demigods and magicians have to team up to take them down. As they battle with Celestial Bronze and glowing hieroglyphs, the four heroes find that they have a lot in common -- and more power than they ever thought possible. But will their combined forces be enough to foil...