Summer in the year 1234. Two men, as different as they could possibly be, are on their way to Cologne. Osman Abdel Ibn Kakar, a Muslim from Alexandria, is fleeing from his master. He is accompanied by Robert the Slim, his best friend. Along the way, they meet the great scholar Albertus Magnus at a Dominican monastery in Hildesheim. The monk confidentially reveals to them his papal mission: to create gold from lesser elements. Shortly thereafter, when he is kidnapped, suspicion falls on the two travelers. The beginning of a life-and-death chase.