Go to The Gallows and look for a Templar named Thrask. He will tell you about a young mage who has gone missing. After accepting the mission, go to Lowtown (Night) to continue the hunt. A man named Samson is waiting not far from where you arrive. You can either pay him in silver or threaten his life for answers about the runaway mage.
Redwater Raiders will be waiting almost as soon as you enter The Docks. There are two groups of them, and they primarily attack with swords and shields.
Try and get the Raiders clumped together in a pack so you can get them all with an area attack.
Go north and enter the door near the arrow. An Abomination will attack along with several sailors. Abominations are tough but not that power. Leave the area and use the map to get to Darktown.
Head south toward to the arrow to find a pack of slavers. After a brief conversation, they will attack. Use an area attack as soon as the encounter begins, then hustle back to the stairs.
Head south along what should be familiar territory. Watch out for Qunari mobs chucking arrows at you. Kill them quickly with area attacks and other skills. Enter the Slaver Caverns. Run up the stairs and use the chokepoint to kill them piecemeal. Follow t
Feynriel will speak with you after the encounter is finished. You can either opt to send him to the Circle, or allow him to live among the Dalish. With the quest completed, you will receive three more gold pieces for your trouble.