Retrieve a Twilight Caravan Gatestone. The Spearwardens should carry keys that can get you into the gatestone chests.
The gates further down the canyon are shut. Our scouting revealed some kind of stone that they carry in chests in their caravans that they use to open the gates.
Get down there and look for a chest key on the bodies of the guards. When you find it, use it on one of those chests on the caravan wagons and bring the gatestone back to me.