The year is 1147. Trier is on the brink of the Second Crusade. While the city is in turmoil awaiting the Pope, an enemy of the powerful archbishop is found dead in his own blood. The clever convent student Laetitia sets out to find the murderer and must confront a fanatical Templar. She uncovers a trail leading to a mysterious alliance and reveals a diabolical conspiracy that reaches into the highest echelons of ecclesiastical power and surpasses all imagination.