A barrel with fish will speak to you inside of one of fish warehouses.
Speak with it and you learn that the barrel is a man called Higba who is wanted by magisters. During this conversation you can decide what you want to do with him.
Choice 1: You told magisters
In this variant you should not promise Higba that you will help him. Instead, you should select a dialog option that doesn't indicate what decision you want to make. Then, you must go to the nearest magister and inform them about the wanted and his location.
That magister will head towards Higba's location and initiate a fight. You can join it if you want.
Reward: 4,000 experience points
Choice 2: You promised to help him
If you decided to help Higba then your goal is to transport him outside Driftwood in a such way that he won't be seen by magisters. The best way is to go through fish warehouse and head towards a shallow passage through the river.
You can also use Teleportation spell.
Reward: 3 guaranteed rewards + 1 out of 4 that you can choose from depending on character's class + Hero tag