This quest can be acquired from executioner Hermann, who can be found at his house west of Rattay. Ask him about what has been troubling him and he will explain that there is to be an execution in Rattay, which he has not been chosen to oversee. You must therefore help Hermann to sabotage the visiting executioner's job.
Once you have spoken to the Bailiff, you should find the Black Chronicle - the book which details the appropriate punishments for specific crimes - in the Rathaus. The book can be found in a room on the top floor, but you should first knockout the scribe to ensure that he does not detect you. After picking the lock to the door opposite the scribe's bed, you can find the book on a pedastel beside the window.
Take note of the contents in the book and then return to executioner Hermann. You must now determine the likely punishments for each individual:
-- Peter of Dauba - He's for the chop.
-- Georg Weis - He'll be hanged.
-- "Frost" Heralta - He'll be tortured first.
Once you have suggested the likely punishments, exhaust the dialogue options and discuss how each method might be sabotaged so that the executioner is publicly embarrassed. You can now make your way to the executioner's camp.
Note: You will need to acquire a vial of poison in order to poison the flesh-ripping tongues. Be sure to craft or purchase one before you go to the executioner's camp. In addition, you can consume an Aesop potion to ensure that dogs do not bark at you for 10 minutes.
As you approach the camp you will notice that it is fairly well guarded. It is also classified as a private area. You will therefore need to rely on stealthy infiltration. Remove any items with noise ratings to minimise the risk of being caught, and wait until dark before attempting to infiltrate the camp. Be wary; even at night there is still one guard on patrol.
Dulling the Executioner's Sword
You will have to pick the lock of the chest inside the tent, steal the executioner's sword, take to to a grindstone to blunt it and then return it to the chest. You will know the sword is blunt enough when Henry verbally acknowledges it after leaving the grindstone minigame.
Poisoning the Flesh-Ripping Tongues
Once you have poisoned the tongues take a few moments away from the camp to avoid anyone spotting you in the disturbance.
Switching the Executioner's Rope
Once you have sabotaged every item, return to executioner Hermann. Inform him that everything is ready and he can allow the execution to proceed. You can now go to the marker on the map and wait until 2pm the next day for the execution to begin. Watch the execution unfold and then go back to Hermann to complete the quest.