Activate this quest to team up once again with Baranor, who somehow managed to track you down.
Your mission here is one of rescue- you'll start with the three Gondorians staked right out in the open here (funny how you missed seeing them on the way in...).
This is just like rescuing Gondorians with Idril earlier- you can cut them free or Baranor can, and you don't have to stealth the orcs, but it's probably easier if you do. Free the third and final captive to get an objective in the nearby cave.
Infiltrate the cave the same way. Do make a point of killing or dominating any hostiles you see- there's a boss battle just a few hundred feet away, and you don't want too many blades at your back.
Defeat the captain downtunnel, and free the five designated prisoners to get one final objective for one final prisoner.
Follow your marker to trigger a cutscene, get a lead on Idril, and complete the mission.