This quest can be obtained by traveling to Lakeside Hut and to the right side the hut by inspecting the dead drowner's body. Once inspected, keeping on moving up and inspecting the dead drowner's bodies until you find a cave to the right, upon entering it, an ancient troll will confront and fight you. Once the troll is defeated, look around with your witcher senses and you will find an old letter which reveals details to the original plan to attack Kaer Morhen.
- Use your Witcher Senses to find out what's killing downers near the lake.
- Kill the troll.
- Search the troll's lair.
- Read the letter.
- While walking along the shore of the lake near Kaer Morhen, Geralt came across the body of a drowner. The witcher thought at first that Lambert or Eskel had killed the creature - but upon closer inspection he soon discovered there were no marks dealt by sword or Sign. It was thus clear someone - or something - else had done the drowner in. They say the enemy of one's enemy is a friend, but Geralt wanted to see who exactly this downer-killing "friend" was.
- It turned out the drowners had perished at the hands of an old rock troll who clearly did not want them as neighbors. He didn't seem fond of Geralt's presence, either - or at least, it seems safe to conclude as much, given that he tried to tear the witcher to shreds as soon as he saw him. Witchers make tougher opponents than drowners, however, and the troll was soon cut down. Geralt then uncovered a very interesting document in the troll's cave that shed new light on the Salamandra's attack on the fortress year prior.
- It's possible to trigger this quest during the main storyline quest The Final Trial, which takes Geralt to the same hut. Geralt can optionally put Final Trial on hold in order to complete this brief mission.