Women are disappearing off the streets of Vienna in 1684 and Captain Mathis Zieglar vows to find out why. Defying orders to break off his investigation, he discovers they are being trafficked into the Muslim slave market. His only hope of ransoming them from a life of abuse is to find the treasure of the Raven King. The treasure is a secret code lodged inside an ancient text that will rock the Ottoman and Holy Roman Empires to their foundations.