Despite initial suspicions, the Dunlendings have decided to let you in on the situation.
'These half-orcs serve a wizard who is bent on spreading his war as far as he can. We planned to assassinate the half-orc leaders, but Riderch was captured in the attempt. Rescuing him put the entire camp on high alert.
'Since we are currently one short, you can act as the distraction. Fight the half-orcs so that the three of us can move in undetected.'
You should defeat half-orcs in Nímbarth to help create a distraction for Meriona and her scouts.
You've created enough of a distraction for Meriona and her scouts to carry out their mission.
You should talk to Meriona outside of Nímbarth.
You should return to Tharbad to let Riderch know that his kinsmen are safe.
Stonecrop Encampment is south-west of Nímbarth.