On the outskirts of Vienna, four women's bodies are found – buried strictly geometrically at a distance of 666 meters from each other. Everything points to a ritual murder. For Rex and Moser, a race against time begins: Who will be the next victim? The trail leads to a remote castle, the headquarters of a sect. There, Moser and his colleagues initially search in vain for clues: the work is hindered by cult members. But Moser is able to cleverly evade his watchdogs and discovers Anne, a young woman who is to be consecrated to Satan. At the last minute, Anne escapes from the sacrificial ritual at Moser's house. But she knows too much: the persecutors don't let up. But not only Moser and Anne are trapped, Moser's girlfriend Sonja is also threatened. Then Rex intervenes – a life-and-death battle begins...