Unfathomable Depths begins with a jittery Argonian on the docks of Riften in the Rift, desperate to get rid of a Dwemer lexicon she helped steal. Your job is to carry it back to the ruins of Avanchnzel, while the ghosts of the expedition that took it replay their final, unlucky days around you. It is part dungeon crawl, part ghost story.
How to start
Reach level 14, then visit the Riften docks. From-Deepest-Fathoms will not appear before that level. She is despondent and paranoid, pushes the lexicon into your hands almost immediately and pleads with you to take it back to Avanchnzel.
Walkthrough
Avanchnzel
Avanchnzel is locked until this quest is active. At the bottom of the first large cavern stand four glowing orange figures: the ghosts of the adventurers (they call themselves thieves, although none of them can pick a lock) who came here for the lexicon. As you follow the quest marker they keep reappearing, and their conversations reveal the story. The two humans had little idea what they were after, but From-Deepest-Fathoms and Watches-The-Roots knew both the ruin and the lexicon well and talked them into staying. The humans stayed because the pay was good; the Argonians wanted the knowledge the lexicon holds.
Expect Dwarven spiders, spider guardians and spheres along the corridors.
Avanchnzel Animoncultory
Fight past the automatons, climb the stairs and continue down the corridor past a tent with four bedrolls, the expedition’s old camp. In the next room, be careful when opening the door on the right, as it is trapped. Keep going until you reach a big hall with two Dwarven Centurions lying on stone tables. In the room after that lies the body of Drennen, one of the adventurers, who split from the group for reasons nobody explains.
Avanchnzel Boilery
As you enter the Boilery, the three remaining ghosts argue about the lexicon and what to do with it. Further on they reappear in front of a door, hurrying towards the Receptacle. In the next room you find the body of Watches-The-Roots.
Through the final door is a large hall with the body of Breya, the last of the explorers, and a Dwarven Centurion guarding the Receptacle. A handy trick is to lure the Centurion into the spinning blade trap in this last room.
Place the lexicon
Activate the Receptacle. The lexicon leaves your inventory, opens up, and you receive the Ancient Knowledge bonus. The quest is now complete.
For a quicker way out, take the door behind the Receptacle, pass through the barred doors and exit onto the Avanchnzel Balcony, where a locked chest offers some extra loot.
Rewards
- Ancient Knowledge, a permanent active effect
- Locked chest on the Avanchnzel Balcony plus Dwemer loot throughout the ruin
Tips and notes
- Ancient Knowledge stacks with the Warrior Stone; together they make Smithing improve 35% faster.
- From-Deepest-Fathoms is not essential. If she is killed, the lexicon stays in her inventory and can still be taken.
- Pickpocketing the lexicon from her also starts the quest; she reacts as if you did her a favour. If you put it back on her, she still refuses to take it.
- Picking up Dwemer weapons such as Dwarven bolts here can trigger a courier letter from Calcelmo, who wants one in exchange for a good payment.
- It is easy to get stuck in the south-east corner of the room where the ghosts debate whether the automatons are sleeping or waiting.
- Some of the imagery, including a skeleton hanging over a pit of spiders, appears to reference William Blake’s The Marriage of Heaven and Hell, a work about forbidden knowledge.
