An earthquake in Israel kills hundreds and reveals a subterranean temple holding the crucified body of a mummified girl. Sergeant Jordan Stone, a military forensic expert; Father Rhun Korza, a Vatican priest; and Dr. Erin Granger, a brilliant but disillusioned archaeologist are sent in to explore and find themselves in a race against an enemy like no other, to recover a book rumored to have been written by Christ's own hand.

From crumbling tombs to splendorous churches, Erin and her companions must confront a past that traces back to a time when ungodly beasts hunted the dark spaces of the world, to a moment in history when Christ made a miraculous offer, a pact of salvation for those who were damned for eternity—creating a secret sect within the Vatican, one whispered as rumor but whose very existence was painted for all to see by Rembrandt himself, a shadowy order known simply as the Sanguines.