The Dunlending village of Brôntrig is protected by many sentries...sentries which hinder any attempt by the Rohirrim to exact retribution for the assaults on their people.
'The Dunlendings at Brôntrig are assuredly to blame for the attacks on my patrols, but the village is protected by many sentries who are in a position to warn their kinsmen should we approach.
'If we are to exact retribution upon Brôntrig for the deaths of my warriors, we will need to rid Brôntrig of these sentries.
'Search the hills and valleys due west of Brôntrig and dispose of any sentries that you come across.'
Travel south along the base of Dol Baran and look for sentries amongst the hills and valleys.
You should seek out and defeat any Dunlending sentries that you encounter.
Ardwyn is at Forthbrond, north of Brôntrig.
You should return to Ardwyn and let him know that you have dealt with the sentries.