Talk to Commander Lothar to learn of the Deserters.
Head east out of the Army Camp and down into the Thylysium slums. Follow the paved road east at the first junction, north at the second junction, and northeast at the third junction to find Scout Randell.
Talk to Scout Randell, then continue north along the paved road to where the three Deserters are.
Kill the three Deserters, then return to Commander Lothar for your reward.
You can now talk to him again for the next quest in the chain, Wet Graves.