There you will find a Boatwright, defeating him is the next objective. After defeating the Bloody Baron head a distance South of Crow’s Perch to Oreton, a small village on the shore. Challenge him to a game of Gwent to unlock the quest, beating him is the first objective. After you agree to search for his family and check the area for clues he will return to his room.
You can obtain this quest when you encounter the Bloody Baron during the main quest line.