Constantinople, 1203. As the rapacious armies of the Fourth Crusade lay siege to the city, a small band of Templars infiltrate the imperial library. They escape with three large chests filled with explosive secrets - ones they will not live long enough to learn. Vatican City, present day. In the hidden archives of the Inquisition, FBI agent Sean Reilly has no choice but to violate the trust he has earned. A vicious terrorist has kidnapped Tess Chaykin, and the key to her freedom lies in this underground crypt, where a secret could explain the real reasons for the Templars' extermination and bring devastation to our world. A pulse-pounding manhunt takes Reilly and Tess across the world as they follow the blood-soaked trail of their enemy, a devious, uncompromising foe unlike any they have battled before ...