When a devastating earthquake in Masada, Israel, reveals a tomb buried in the heart of the mountain, a trio of investigators - Sergeant Jordan Stone, a military forensic expert; Father Rhun Korza, a Vatican priest; and Dr Erin Granger, a brilliant archaeologist - are sent to explore the macabre discovery, a subterranean temple holding the crucified body of a mummified girl.

But a brutal attack at the site sets the three on the run, thrusting them in to a race to recover what was once preserved in the tomb's sarcophagus: a book rumoured to have been written by Christ's own hand, a tome that is said to hold the secrets to His divinity. But the enemy who hounds them is like no other, a force of ancient evil directed by a leader of impossible ambitions and incalculable cunning.

From crumbling tombs to splendorous churches, Erin and her two companions must confront a past that traces back thousands of years, 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.

Here is a novel that is explosive in its revelation of a secret history. Why do Catholic priests wear pectoral crosses? Why are they sworn to celibacy? And why does Catholicism insist that the consecration of wine during Mass results in its transformation to Christ's own blood? The answers go back to a secret sect within the Vatican, one whispered as rumour but whose very existence was painted for all to see by Rembrandt himself, a shadowy order known simply as the Sanguines.