Contract: Missing Miners is a witcher contract in Skellige. Young men from the village of Blandare set off into the nearby mountains looking for silver, and their expedition went badly wrong. Geralt is asked to find out what happened to them.
The answer lives in the caves near Blandare: a rock troll named Wham-a-Wham has made his home there. Rock trolls are, in their own way, thinking creatures, but they are often cruel and violent towards humans, and this one is no exception. Geralt learns that the miners knew the cave was inhabited, and that the troll warned them he did not like uninvited guests. They came anyway.
That gives Geralt a choice that Witcher 3 players will recognise. He can kill the troll and claim the bounty, or talk to him and let him live, knowing that the miners walked into his home despite the warning. Both options have their own rewards, and neither brings the miners back.