The video above is the The Witcher 3 Wild Hunt The Nithing Secondary Quest Walkthrough and shows how to complete The Nithing, the quest featured in The Witcher III: Wild Hunt.
The video walkthrough covers the following objectives:
Talk to Lothar.
Investigate the Nithing.
Follow the tracks and scent using your Witcher Senses.
Ask about the shawl’s owner.
Talk to Jonna, the herbalist.
Talk to Lothar about how to lift the curse.