According to the magistrate, the pirate you captured is too important a prisoner to waste his execution locally. So he wants you to bring him to a nearby town and hand him over to the authorities there.
You will have to go to a nearby town for this mission. On starting it, it turns out to be an ambush that pits you and about 5 NPC allies against a large fleet of pirate ships (all between levels 5 and 8). Your enemies will abandon ship long before their ships would have sunk. Defeat them, then enter the target town to talk to the local magistrate there. After this you can return to claim your reward and get the follow-up mission.
- Defeat all Enemy Ships: 0/8