Head to the small island east of Redgill to find a journal and a body near the tree. Read the journal to start the quest, then examine the body and the zebra crest on the nearby wrecked ship to conclude they're not from the Northern Realms nor Nilfgaard.
Head to the southern part of the island to see a mostly sunken ship mast and dive down to find a chest containing a letter sealed with impermeable wax and the captain's log. You can read the letter but it's in another language. However, the log gives more insight into things and points to your next location: Ursten, a small village south of Novigrad.
Head to Ursten where what you do next will cause a slight difference in conversations. If you talk with the warrior in town, you won't be able to talk to the woman later, though you can still decide the outcome (you just won't be able to give her the documents).
Whether or not you talk to the warrior, head out on the coast just southeast of Widows' Grotto, to find the second ship. Examine its hull to find the same zebra crest, then the nearby ground for footprints and follow them until you see a woman at a watchtower who flees as soon as you try to get close. Run after her or continue following the tracks around and eventually they'll come to the entrance of the nearby grotto.
If you didn't talk to the warrior beforehand: the woman will be yelling at you as you approach. You can try to talk with her but she doesn't understand you so hand over the captain's log, then the letter (if you do the letter first you can't give her the captain's log as you'll be interrupted). After you do, the warrior will approach.
If you talked to the warrior in Ursten beforehand: at the entrance to the cave will stand the warrior, who the woman is yelling at instead.
Regardless how you met the woman, as soon as the warrior approaches she'll try to shield the child and the warrior starts talking to her in the unknown language before telling you that the woman is a criminal and took the child and he's to return the boy home. You can either agree to side with him or not.
If you side with the warrior, he'll proceed to cut the woman down, ending the quest.
If you side with the woman, you must fight the warrior and, once dead, the woman will try to give you a small reward, which you can agree to accept or tell her to keep it. If you accept it, you'll receive a stone medallion before she and the boy leave.
- Geralt ran into a suspicious gentleman who was looking for a woman who spoke in a strange, unknown tongue. He claimed they came from some far-off land far beyond the sea. She had kidnapped a child, and he had been tasked with finding and punishing her.
- On a small isle in Skellige Geralt found a diary written by refugees from a far-off land. Their ship had wrecked and the fate of its passengers was unknown. Geralt hoped at least some had survived and he would one day have the chance to return this diary to them.
- If Geralt talks to the warrior in Ursten:
- In a certain Velen village Geralt came across a strange man speaking with a strange accent. The man struck Geralt as odd, even for a foreigner.
- Read the diary found on the body.
- Find the sunken chest mentioned in the journal.
- Uncover what became of the second ship.
- Search the area around the wreck for any sign of survivors.
- Find the woman to whom the indecipherable message you found on the corpse is addressed.
- Talk to the foreign woman.
- If you didn't talk to the warrior beforehand:
- Take the letter to the woman who speaks an unknown language.
- Even though this quest includes areas of Velen and Skellige, it's not marked as "multiple regions."
- If you examine the footsteps at the second ship before examining the crest, the quest won't update to the next objective. However, if you just follow the tracks they'll eventually lead to Widows' Grotto where you can then continue the quest as normal.
- Sometimes one can meet the warrior beforehand but still get yelled at by the woman, allowing Geralt to give her the documents as if he never met the warrior in the first place. In this instance though, the journal entry will display like he met the warrior.