Meet up with Agarth in the Three Lanterns in Didenhil. He'll tell you his plan. Choose to go in the front door (it's simpler) and you'll set off N to the Hunter's Pit. When you get there, watch out for the two bears outside. Kill them and then go to open the gate.
Room 1: This room is almost castle like. You'll come in and a few Tuatha will warn the others. Watch out for the archers on both sides and the soldiers coming straight up the middle. Kill them and go down the ramp to the rest of the camp. There may be some stragglers here so clean them up.
Hallway: You'll encounter a group of three here but they shouldn't be too tough. Just be aware that dodging may be difficult because of the small amount of space on either side. After these three, clear a bridge of boxes and then two more Tuatha will come at you. Kill them as well.
Room 2: You'll come to a fork in the path. You can go low or high. It really doesn't matter which you choose except that the high road (right) will allow you a better position for ranged attacks while the low road will get you into the thick of the fight faster if you want to charge right in. There will be a small group in the lower area (with a chest) and a couple of archers up high behind them. Take out the archers first, even if that means running right past the first group.
Hallway: You'll come to a thin strip area with a group of four Tuatha. They appear to be primarily melee. Back up a little and you might be able to get them to line up single file, allowing you to use some spells or abilities to hit more of them at once.
Room 3: You'll come to a room with a big red structure. In front of it are a small red crystal and a Tuatha dancing. Sneak up and perform a stealth kill. Break the red crystal and Gadflow will step out of the structure. Talk to him and when he is done, Agarth will appear and talk to you. He recommends that you talk to Alyn Shir. If you haven't already, do so to start Old Friends, New Foes. Before you leave here, you can inspect the area to the south for all sorts of goodies and plenty of breakables. There are also some monsters but they are locked up and won't harm you unless you let them out. When you are done, leave this dungeon and continue on with the Old Friends, New Foes quest.
