Tatort S2015E15 - Voss - 1 - Der Himmel ist ein Platz auf Erden

What the French call "Petite Mort" ends fatally in a forest near Nuremberg. Christian Ranstedt, married and father of two children, professor at the University of Erlangen and respected citizen of the city of Nuremberg, was killed by two shots in the head at close range while making love in his car. When the police arrive, both car doors are open. The driver's seat with the dead Ranstedt is pushed back far. The person who was in the car with him has disappeared. Nothing indicates their identity. Ranstedt's wife Julia believed her husband at the university. For her and her two children, a world suddenly collapses that seemed indestructible. Why was Christian Ranstedt murdered? Why in such a spicy moment? And how come whoever was in the car with him survived?