You start in a little enclosure that you can get out of by talking to Captain Sulahresh. As there are patrols all around you, it is suggested to kill those through the enclosure prior to exiting. Once out, proceed killing everything on your path until you reach the wall. Once all the Margonites in the area outside and on top of the walls are cleared, Captain Sulahresh will come and join you, and the gates will open. He will enter the gate and stop just inside the gate. You will now need to clear the entire middle of the city to proceed. As there is a gate which can be blocked by one person, it is suggested that the appropriately protected member of your party does this, and pulls the mobs to them. Once all the groups in the city are cleared, Captain Sulahresh will give you the reward.