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.
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 to stop the Lord of Time.