Begin by heading up to the Guest Room. On your way there, you will see and hear a magical explosion, followed by her cursing. Approach and you will enter a cutscene, where she will explain that "this was the third crystal" and that she has an urgent call to make. She tells you she suspects there is a disturbance causing the crystals to malfunction, and, entrusts you to find it. After talking to Yennefer she will give Geralt a Potestaquisitor, A quest item which can be equipped, which will hum when near a migical disturbance. Go to the Main hall and use it, following the sound as it gets louder and stronger. The disturbance is near Uma so you may think he is the problem but he is not, nor is it in the wall. It is the crates that contain Dimeritium bombs made by Lambert. Vesemir will take them away while Geralt keeps on eye on Uma. When Vesemir returns, head back up to the Guest Room and talk to Yennefer, and let her know you found the disturbance and what it was. Yen will assume Lambert did that on purpose, and you have the choice to quip that he knew what he was doing, or that he knows nothing about Megascopes. Regardless of your answer, after this, Yennefer will prepare to make her call and tell Geralt to behave himself. Now, Yennefer and Geralt will converse with Ida Emean aep Sivney about Uma's curse and the White Frost. You will be given a few different dialogue options, which can be 'right', earning straight answers and no upset, or, picking any of the wrong ones will earn you immediate disdain followed by a reprimand after Ida's call.
The correct conversation options are as follows:
- Caed'mil, Aen Saevherne.
- (Optional) Know the dialect?
- Heard the words before, haven't you?
- What is it?
After the conversation with Ida, if you picked wrong conversation options, Yen will ask Geralt to apologize for his behaviour to which he can agree or not. If you got them all right, it goes right into the standard dialogue. Needing to apologize or not, you can ask Yennefer if she understood all that, and if you chose the optional "Know the dialect" prompt, about the Migration that was mentioned, then the progressive "What now?" which will lead you into the end of the conversation and onward to complete the other tasks if you haven't already.
- 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.