Lock and Key
During the A Posh Reception quest Leuvaarden will give you the Lock and Key quest. This quest is an overview quest and includes many smaller quests within it. During the reception Declan Leuvaarden will tell you that he also wants the Salamandra gang gone. You’ll need to complete the Following the Thread quest and the Diplomacy and Hunting quest before continuing with this one.
Once those quest are complete return to the New Narakort Inn (#1) and speak with Declan. You should have on you an Encrypted Document and the Key that encrypts it. Declan will send you away so that he can have a look at it and asks you to come back later.
When you come back go upstairs and speak with Declan for an update. He’s located the last Salamandra cell but it’s in a restricted area. He has a spy operating as one of the City Guard and gives you a secret password. You’ll need to wander around and speak to all of the Guard Officers until you find the right one. The third Guard Officer you talk to should be the spy.
The Officer will tell you to meet him inside the Sewers at midnight. Make your way to the Sewer Entrance (#2) and go inside. Continue down to the end of the tunnel to find the guards. They’ve prepared a ladder into the blocked off area. Head into the alley and go through the door to the Salamandra Base (#3).
Kill all of the Salamandra here and then go downstairs to finish off the remaining thugs. Search the bodies. One of them, the mage should have a Power Stone. You’ll also notice that the stranger in the mirror is still available for a chat. This is Radovid, King of Redania.
Take the Seeing Stone from the stand in front of the mirror and then get out of there. Salamandra seem to have invaded this part of the town. As you make your approach you’ll notice a Werewolf also taking out the thugs.
The Werewolf will talk to you. It’s Vincent! At the end of the conversation you’ll have a choice to kill Vincent or to let him go. If you let him go it will aid your progress towards finding the identity of the real killer. If you kill him you’ll have a battle with the Werewolf until it’s almost dead. The Werewolf will turn back into Vincent and you’ll have one final option to spare him or kill him.
It’s time to get out of here. You can’t leave the way you came but the door to the Old Forge (#4) is open. Go inside and head down the trapdoor back into the Sewers.