However you arrive at it, he'll reveal someone planted a nithing just outside his home: the mark of a deadly curse targeted at his young son, Tjalve. Geralt will then reveal 2 ways to undo it and save the boy: either get the caster to remove the curse or Geralt can reverse the curse onto the caster, but he needs to know who cast it first. Lothar is adamant though that he's done no harm to anyone so you'll have to investigate into this if you wish to help.
If you choose to help, examine the nithing then follow the tracks until you find a Skellige shawl with a clear scent trail. This will eventually lead you to Rannvaig, but then it fades off so you'll have to ask around about it. Head towards the harbor to find an unnamed Skelliger woman during the daytime and talk to her, who'll reveal that it belongs to the herbalist Jonna.
Talk to Jonna and she'll admit she planted it, revealing she did it for her dignity: she and Lothar used to be together for 10 years when he suddenly left her without a word and married someone else, making the whole village remark how Jonna had been "had". She'll then agree to lift the curse but for a steep price: Lothar must return to her and denounce his son, which would strip his wife and children of honor and condemn them to poverty. Go back to Lothar and let him know the deal and he'll be upset and all but demand Geralt to turn the curse on Jonna instead. You must now make your choice.
If you wish to not kill Jonna, Lothar will reluctantly agree to go back to her to save his son and will say goodbye to his family, finishing the quest. You can later see that when he does arrive in town, Jonna tries to tell him he'll soon forget about them and she'd bear him healthy sons but Lothar tells her off point blank he only agreed to return to her, not to love her.
If you instead agree to turn the curse on Jonna, interact with the nithing and her name will be carved on the shaft and the skull will be turned around, aiming towards Jonna. Go talk to Lothar to let him know it's done and he'll pay you before asking if you'll stay for dinner, though Geralt declines, completing the quest. A short time later Jonna disappears from the game.
- In Skellige Geralt met a desperate and broken man named Lothar. Someone had cast a powerful curse on his son, causing him to slip closer and closer towards the grave with each passing day. The witcher knew he had to lift the curse before it's too late.
- If you decided to kill Jonna:
- The witcher discovered the curse had been cast by the local herbalist, Jonna, with whom Lothar had once shared the bed. Once again it was proven - something which I, dear reader, know all too well - that man knows no greater enemy than a woman scorned. Geralt was able to save the man's son, but the spell demanded a victim. The disease moved to Jonna, dragging her into a painful and premature death.
- If you decided to spare Jonna:
- The witcher discovered the curse had been cast by the local herbalist, Jonna, with whom Lothar had once shared the bed. Once again it was proven - something which I, dear reader, know all too well - that man knows no greater enemy than a woman scorned. Geralt managed to convince Lothar to return to his one-time love. He had to abandon his beloved son, but in doing so he saved the boy's life.
- Talk to Lothar.
- Investigate the Nithing.
- Follow the tracks using your Witcher Senses.
- Follow the 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.
If you decided to kill Jonna:
- Carve Jonna's name into the Nithing.
- Talk to Lothar to collect your reward.
If you decided to spare Jonna:
- Talk to Lothar, decline his request to redirect the curse.
- Killing Jonna means you'll lose her as a merchant, so make sure to buy what you need from her before doing so if you plan to reverse the curse.
- The Nithing is directly based on the Nithing pole, which was used for cursing an enemy in Germanic pagan tradition.