Direct answer
Objectives follow journal display order. Some depend on your choices; follow the active objective in the game.
Result
On the coast of Ard Skellig Geralt ran into a young warrior - well, he stopped running before he hit the young man, but I believe you get my drift, dear reader - at any rate, the point of my story was not that he ran up to (not into!) this said warrior, but that the warrior was besieged by pirates at the time. Geralt helped him fight off his attackers and listened (with only a slight amount of witcher impatience) to his story, which was as follows: the man's sister had been kidnapped by pirates (not unlike the ones he had just faced), and he was determined to track her down, even if it meant searching all the isles in the Skellige archipelago. He thanked Geralt for his help in dealing with one of what would surely be many patches of pirate trouble and continued on his path.