Herz was part of a group of Nazis, led by Luther, who took over the village of Pax Lucis. They erected a barrier around the village using a captured lightwanderer.
Herz captured the Seventh Doctor and brought him to Luther. Herz could not understand why Luther refused to kill the Doctor, talking to him instead, even when the Doctor tried to undermine their morale. Herz conspired with Franz to remove Luther from command.
Herz was killed with the rest of the Nazis by the lightwanderer when it was freed. (PROSE: Special Weapons)