Jewelry designer Garet James is the Watchtower-the last in a long line of powerful women sworn to protect the world from evil. Although she had once defeated evil in New York City, her pursuit of her true love, the 400-year-old vampire Will Hughes, has now unleashed an age-old evil onto the modern world, and the entire planet is at risk.

Marduk, the ageless descendant of a demonic Babylonian deity, is now loose in Paris. He has joined forces with the villainous John Dee in a plan to destroy the world's economy and plunge the entire world into chaos.

To fight this threat, Garet enlists the help of a modern-day band of knights who are dedicated to preserving the sanctity of the timeline. As she and her allies face this threat, new challenges arise in the form of a rival faction of knights who will stop at nothing to bring about the destruction of everything Garet holds dear.