Dead Man's Chest
Side quest
Skellige suggested level 16
From the journal
Skellige is a nation of sailors. And where there are sailors, there are pirates. And where there are pirates, there's treasure. Geralt was put on the trail of one such hidden cache of pirate booty during his travels in the isles.
The treasure was, as befits one left by pirates, hidden in a coastal cave. Geralt found it and, following the hallowed law of the sea, kept it for himself.