Going to the country of the Cathars - the rocky Languedoc, Pierre Le Bihan, of course, understood that the journey would be dangerous. This land in the southwest of France has always been famous for its ancient ruins, dark legends and terrible secrets. But what exactly was the archaeologist Otto Rahn, crazy about the occult and who joined the Nazis, looking for in these parts so persistently? Templar gold? Holy Grail? Albigensian treasury? Having died under unclear circumstances, the SS man took his secret to the grave, but left a diary. French historian Pierre Le Bihan will have to penetrate the heart of the ancient mountain Montsegur and try to unravel the mystery of Otto Rahn. A secret that he is not the only one hunting for...