Thou Shalt Not Pass is a secondary quest that sees you acquiring a transit pass in order to go through Redanian Border points. The only way to do this is to get the black market pass from a nearby merchant during the quest Fake Papers
|Reward:||Access to Redanian territory|
The Redanian army had placed blockades on the crossings of the Pontar, something which at one point proved quite inconvenient to the witcher. The guards refused to let him cross without showing a special pass issued by high command.
Name: Redanian Soldier
When you try to cross the Pontar river using a bridge, the Redanian soldiers will turn you back. You need a pass.
Following contains quest spoilers. You’ve been warned
Acquire a pass granting permission to cross the Pontar.
You will have two choices when you first talk to the soldier. What it boils down to is that you need to go to the black market merchant and do his Fake Papers quest.