With its defensive automatons deactivated, it is overrun with Falmer, thwarting any attempts to study its artifacts and treasures. Calcelmo asks the Dragonborn to defeat Nimhe, a giant frostbite spider that has halted progress at the dig site. After killing the spider, they gain access to Nchuand-Zel. Alternatively, the lock can be picked for access without needing to talk to Calcelmo. If picked, it is an adept-level lock. The key to Nchuand-Zel can also be pickpocketed from Aicantar.
The entrance to Nchuand-Zel is a large chamber with several sections. The men working in Nchuand-Zel attempted to block the Falmer from entering the ruins, but the creatures were too strong for the men to hold back. While exploring the Armory, Quarters and Control, the Dragonborn finds notes and journals from the men who were working in the ruins along the way.
After completing "The Lost Expedition" and activating the Dwemer defenses, the Dragonborn can witness a short fight between Dwemer Automatons and a few Falmer.
Upon entering, the Dragonborn will be looking down a small hallway. Go down this hallway—minding the fire trap—and get ready to face a Falmer on the bridge ahead. He can be killed easily with a sneaky shot from a bow. There will be three more Falmer along this bridge (Note: The second Falmer may fall into the water below if it is alerted by sneak-killing the first Falmer. Falling into the water will kill him instantly). After those two, there is two more Falmer on the bridge before the door. The final two are stronger than the first two.
Walk down the hall. To the immediate left (east) there are two pieces of scrap metal. To the right there is a mounded Centurion head. Continuing, the Dragonborn will see another Falmer upon rounding the next corner. He will not see them, so they can sneak-kill him easily. Killing him will alert another Falmer, who will subsequently ascend the staircase. Passing the stairs and continuing down the hall, the Dragonborn will meet a single strong Falmer. Keep going and to the right (west) there is an adept-locked gate. Behind it is some scrap metal, random armor pieces, a potion, and a Dwemer chest containing random leveled loot. Down the stairs, the Dragonborn will meet several Falmer. Finish them off and continue. Another Falmer will be positioned atop the small stairway in the next room. Engaging him will alert a couple more who will attack. Finish them off and go up the stairs.
In the next room the Dragonborn will be returned to the door to Nchuand-Zel. They must go back the way they came until they find the stairway leading down. Go down the stairway and continue through the hall. Prepare to fight a few Falmer at the next stairwell after looting a couple of dead Falmer. Go up the stairs (beware the fire at the top) and get Stromm's Diary. There is also a dead Falmer in this area.
If the Dragonborn continues down the hallway, they will soon come to two dead Falmer. There is nothing in the next room except poison on the small blood-covered table and a torture trap to play around with (pull the lever on the right of the doorway to activate. It will not hurt the Dragonborn).
Go back the way from which this area was entered, and go back through the door to Nchuand-Zel. To the left (west) and then left again (south) onto the small platform, is a pathway that can be followed down.
At the bottom of the pathway you can turn left (east) to cross a bridge where you will see a Falmer. Head back up to where you just came from and turn left (south) onto another small platform, down to the bottom level where there is an Adept-locked gate with a chest inside. From here you can swim to the Nchuand-Zel Armoury on the west wall.
Upon entering the Armory, the Dragonborn will be met with a two Falmer just up the stairs. After dealing with them, head right (north) and battle a stronger Falmer and his pet, a Skeever. When they are dead, go left (west) down the stairs (beware the fire trap. It is likely it will not touch the Dragonborn, but any followers will be affected.) Turn left again (south) (beware of a spike trap; the spikes will come from the walls of the doorway) and down the small staircase in the doorway. In the next room there are inactive Dwarven Spheres and Dwarven Spiders, as well as the body of a Falmer and Erj. Search his body for his Notes. Behind Erj is a chest containing leveled loot. Four gates around this central room can be opened for loot.
Just back up the small staircase on the right (north) wall the way you came, head forwards up a staircase to find yourselves at a door back to Nchuand-Zel.
This door will lead you to a platform where you'll find the body of Krag, which you should search for his Journal. There is also the Alteration skill book Sithis on the bench next to him, and on the bed roll furthest from the door is a sack containing ingredients or food items. Turn left (north) up the path, past an Imperial corpse, to the door to Nchuand-Zel Control.
Upon entry, follow the path forward, and when you turn left be careful of the pressure plate (arrow trap) in the middle at the bottom of the ramp. Kill the pair of Falmer at the top and head left (west) down the next hall. Be careful of the spike trap in the doorway and kill the next pair of Falmer in the next room. Turn left (south) and search Staubin's body for his Diary.
Continue on and there are several Dwarven Spiders to battle. Head up the double staircase, and continue around this area. There are two dead Dwarven Spheres carrying varying soul gems and a Falmer to kill. Up a small staircase and to the left (north) there is a small room with a chest to loot, lever to pull and potion to grab. This lever reactivates the Dwarven automatons in the ruins, which will take out the Falmer so the expedition can go on: now is time to leave.
Continue down the hall past the now-opened gate on the right (east) of this room. Head to the end of the path and find an unlocked Dwemer chest. Jump off of this bridge to the lower level and turn south, back out of the entrance door directly by where you land.
Head up a dark dirt path immediately to the left (north) of the door. From this upper platform you can easily kill the Dwarven Centurion, which was fighting Falmer on Krag's platform since you reactivated it, with long-distance attacks, as it can't climb the path and can't retaliate. Jump back up onto the dirt path to loot the dead Centurion and then return up the dirt path, through the doorway to the left (north), along a corridor to a door back to the Excavation Site.
- Moonstone ore vein next to the entrance to Nchuand-Zel Control.
- Nchuand-Zel is littered with Dwemer artifacts which can be smelted into Dwarven metal ingots for the enterprising smith. There is enough salvage to create over three-hundred ingots.
- In the armory, behind an Expert-locked gate on the right of the Centurion statue, is a full set of Dwarven Armor.
This section contains bugs related to Nchuand-Zel. Before adding a bug to this list, consider the following:
- The quest marker leading back to "someone who knows about the expedition" is glitched. It will lead through the Armory and down to the lower level, and then over to a wall. The quest marker indicates a door, but there is no door here. Ignore the marker and go back to the Excavation Site. This will fix the problem. The marker will now lead to Understone Keep, where Calcelmo can be spoken to and the quest "The Lost Expedition" can be completed.
- The game has a high chance of freezing inside the ruins. Make sure to turn off the Auto Save function, as this seems to make the game freeze even more, and make manual saves frequently. This will help the game considerably, but the game still can freeze, especially when entering or exiting the Armory.
- After the lever in Nchuand-Zel Control is pulled and the automatons are reactivated, three of the Falmer that spawn with them are noticably smaller than the rest, with one of those three being so small that it's easy for them to miss when trying to attack the Dragonborn.