Brilliant Egyptologist Dr. Julius Kane accidentally unleashes the Egyptian god Set, who banishes the doctor to oblivion and forces his two children to embark on a dangerous journey, bringing them closer to the truth about their family and its links to a secret order that has existed since the time of the pharoahs.

When Apophis, the chaos snake, threatens to plunge the world into eternal darkness, siblings Carter and Sadie Kane plan to use an ancient spell to destroy the snake, but first must rely on the murderous ghost of a powerful magician.

When the goddess Artemis disappears while hunting a rare, ancient monster, a group of her followers joins Percy and his friends in an attempt to find and rescue her before the winter solstice, when her influence is needed to sway the Olympian Council regarding the war with the Titans.

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.

Features essays on Percy Jackson's popular world by such authors as Jenny Han, Cameron Dokey, Paul Collins, and Ellen Steiber.