The Witcher 2 – Assassins of Kings: Finding the Key to the Temple
In order to enter the temple at the end of the prologue in The Witcher 2 – Assassins of Kings first you must go back into the town below. Once here you may wish to walk around saving the locals from marauding soldiers or you can start looking directly for the group of prisoners have been lined up against a wall by the kings men.
Break the wooden wall to the left of them using your Aard sign and make your way down the alleyway. At the end of the ally drop down the well and follow the path until you see the king on the other side of a gate. Here you must kill all of your enemies as one of them will have a key. You can enter the temple this way by returning to the previous room and opening the gate.