The Knights Templar in this book do not wear armour, but Scout uniforms; they are fresh boys of the Panther and Seagull patrols on their Whitsun trip in the south of France. But with the same pride as those medieval warriors they wear the Knights Templar cross, along with the scout lily, as a symbol of their troop name. None of the boys would have dreamed that they would be drawn into a tremendous adventure through this. Who is the mysterious Dark One? Where did Torti go? Are the riddles solved at the Cathar Castle? This is not a fictitious story; it was really experienced, and is described to us in a gripping manner by Otto Lohmüller, the leader of the happy band, who also contributes the illustrations and expressive portraits as well as the painting and the design of the title.