July 15th, 1099. As Jerusalem's walls fall to the victorious Christian army and the massacre of townsfolk begins, Izz al-Din, a dying Fatimid soldier, pledges his soul to a demoness. She gives him time. Time to bide. Time to avenge his murdered wife and children. Time to exterminate the descendants of the Frank commander to whom he surrendered.

Nine hundred years later, Izz al-Din's bloody pursuit of Charles Hauteville and his son Marcus is interrupted by the discovery of five blastocysts made, supposedly, with DNA taken from a Templar relic present at the Crucifixion.

Izz al-Din's theft of the blastocysts and the appearance of a ruthless Vatican envoy lead to a violent inversion of roles and a race to find and destroy Izz al-Din before he can birth the Antichrist.