After talking to Yennefer she will give Geralt a Potestaquisitor which will hum when near a migical disturbance. Go to the Main hall and use it, the disturbance is near Uma so you may think he is the problem but he is not, it's actually a crate left from him that contains Dimeritium bombs made by Lambert. Vesemir will take them away while Geralt keeps on eye on Uma, after that return to Yen, who will assume Lambert did that on purpose. Now Yen and Geralt will be conversing with Ida Emean aep Sivney about Uma's curse and the White Frost. After that if you picked wrong conversation options Yen will ask Geralt to apologize for his behaviour to which he can agree or not, or if the right ones were picked the conversation end and it's time to move on with the rest.
- Vesemir told Geralt that Yennefer had set up her trusty megascope as soon as she arrived at Kaer Morhen, but could not get it to function for the life of her. This news greatly troubled the witcher. If Yennefer was planning to use her megascope, that meant a conversation with other sorceresses was in the works – and that in turn meant scheming, politics and other things Geralt truly could not stand.
- As expected, Yennefer did not extend Geralt the warmest of greetings. Nevertheless, Geralt, ever the noble and patient soul, helped the sorceress eliminate the source of the magical disturbance. It turned out the culprit was a case of dimeritium bombs Lambert had carelessly placed near the sorceress' room. Tsk, tsk, Lambert.
- Find and help Yennefer.
- If Geralt rejected Yennefer in The Last Wish (quest) and chooses to argue with Yennefer in the beginning of this quest, she will teleport Geralt to the lake near the Kaer Morhen keep
- Return to Yennefer.
- Find the source of the magical disturbance using the potestaquisitor.
- Let Yennefer know you removed the source of the disturbance.
- The source of the disturbance is in the boxes to the left of the cage next to Uma and Vesemir.