Head to the Viscount's Keep and talk to Aveline in her office. Accept her task and find Guardsman Donnic in the next room over. Talk to Aveline after the task is complete to receive another one. Complete this as well and continue to play out this little game until you are to go to The Hanged Man at night. Approach Donnic at this time but Aveline backs out. This time she wants you to go to The Wounded Coast.
Begin moving along the northern path until you reach a path leading to some Embrium and a pile of bones . Further ahead is the Signal Fire. After this first one move west to find another, guarded by Raiders of course. From here head south checking the pile of bones and crates along the way. Search the sack and light the other Signal Fire to start a confrontation.
Return to Viscount's Keep and talk to Aveline once more to finish the quest.