Contract: The White Lady - Novigrad
Location: Farcorners' area
Quest Giver: Farcorners' Notice Board, Examining tower or bodies
Other Requirements: N/A
This quest can be started by accepting the contract from the Farcorners' Notice Board or by examining the bodies involved in the quest. You can also start this quest by climbing to the top of the tower and examining the portal marker on the ground.
After speaking to the contract issuer you will want to travel to the spot marked on your map/compass. Inspect the three bodies here and the foot prints to update your task and send you to the nearby tower. This tower is also a treasure trove of hidden goodies so along with using your Witcher Senses to do this quest make sure you collect all there is here to find.
At the top of the tower in front of the chest you'll find a portal to examine on the ground and next to the tower in the destroyed building you will find blood stains that go down into the cellar. In the cellar you'll find some bodies, inspecting all of these will update your quest and you'll conclude you're up against a Noonwraith.
Return to Helga and speak with her to update you quest again and receive a dagger which you'll need to use to summon the Noonwraith. Return to the first place where we found the bodies and toss it into the fire to summon the wraith.
If this if your first time facing a Noonwraith there are some things you should know before charging in. First and foremost, you can only deal damage to the Noonwraith while she is in your Yrden circle. For this fight you're going to basically want to drop Yrden on the ground then never leave the circle. As the Noonwraith enters it to attack you, that's when you strike.
Noonwraith Weaknesses: Specter Oil, Moon Dust and Yrden
Once you've defeated the Noonwraith then you'll want to return to Helma, the contract issuer and speak with her to turn in the quest.