Unfathomable Depths

Unfathomable Depths is a quest available in in which the Dragonborn must return a Dwemer lexicon to the ruins of Avanchnzel from where it was taken by From-Deepest-Fathoms and her companions.
==Background==
A disturbed Argonian named From-Deepest-Fathoms was wandering the Riften docks. She wanted me to take something she referred to as a lexicon back to Avanchnzel.
==Objectives==
#Speak to From-Deepest-Fathoms
#Take the lexicon to Avanchnzel
==Walkthrough==
===Riften Docks===
The Dragonborn will find From-Deepest-Fathoms wandering around Riften's docks. Upon first meeting her, she seems despondent and paranoid, immediately wanting to give the lexicon over to the Dragonborn, pleading for it to be returned to the Dwemer ruins of Avanchnzel.
===Avanchnzel===
Upon arriving at Avanchnzel, four transparent orange figures will be standing at the bottom of the first large open cave room. These are the "ghosts" of four adventurers (or "thieves," in their own words, although none of them can pick a lock), who went to Avanchnzel to recover/steal the Lexicon.
They will reappear throughout the quest and the Dragonborn can overhear that the two human characters had little knowledge about the place or item of interest, but From-Deepest-Fathoms and Watches-The-Roots were very familiar with both and persuaded them to stay and complete the job against their better judgement. The two human mercenaries stay, only because the job paid well, but it becomes clear that the Argonians sought out the Lexicon for the knowledge it housed.
When following the marker along the corridors, the ghosts will reappear along the way. Dwarven Spider Workers, Dwarven Spider Guardians and Dwarven spheres are found on the way.
===Avanchnzel Animoncultory===
Fight the Dwarven enemies and continue forward up the stairs and corridor, passing a tent with four bed rolls used by the adventurers when alive.
Beware of the trap when opening the door on the right in the next room. Continue through rooms and doors, eventually coming to a large room with two Dwarven centurions on large stone tables.
In the next room, one of the adventurers, Drennen, is lying dead on the floor. He left the group for unknown reasons.
===Avanchnzel Boilery===
Upon entering the boilery, the three remaining ghosts talk about the lexicon and what to do with it. Moving forward through rooms and corridors, the ghosts reappear before a door and they are in a hurry to reach the Receptacle. In the next room, there is the second dead explorer, Watches-The-Roots.
Finally, through the last door, there is a large room with Breya, the last of the explorers, lying dead on the floor. A Dwarven Centurion is guarding the Receptacle in which to place the Lexicon. This Centurion can easily be defeated by luring it into the spinning blade trap in the last room.
Upon activating the receptacle, the Lexicon will be removed from the inventory and open. The Dragonborn will be rewarded with Ancient Knowledge, a permanent bonus. The quest will now be completed.
Leave by the door behind the Receptacle and go through the barred doors and out to the Avanchnzel Balcony for a faster exit and a locked chest with some loot.
This dungeon is not accessible before the quest has been activated (Dungeon Lock Outs).
==Journal==
Unfathomable Depths – MS04	Unfathomable Depths – MS04
ID 	Journal Entry
10 	A disturbed Argonian named From-Deepest-Fathoms was wandering the Riften docks. She wanted me to take something she referred to as a Lexicon back to Avanchnzel.
*Objective 10: Speak to From Deepest Fathoms
100 	A disturbed Argonian named From-Deepest-Fathoms was wandering the Riften docks. She insisted I take the Lexicon she gave me back to Avanchnzel.
*Objective 100: Take the Lexicon to Avanchnzel
900 	I've returned the Lexicon given to me by From-Deepest-Fathoms to Avanchnzel.
1000 	I've returned the Lexicon given to me by From-Deepest Fathoms to Avanchnzel.
*Quest complete
==Notes==
*From-Deepest-Fathoms will not appear until the Dragonborn has reached level 14.
*Pickpocketing or just taking the lexicon from From-Deepest-Fathoms and then placing it back in her inventory will cause her to still act as though the Dragonborn has it and will say "No, It's yours now, I won't take it back I won't!," even though she has it in her inventory.
*From-Deepest-Fathoms is the only person the lexicon can be placed on.
*From-Deepest-Fathoms is not marked as an essential character so she can be killed if attacked. The Lexicon will still be in her inventory after she dies.
*Stealing the Lexicon only results in From-Deepest-Fathoms turning around and talking as if the Dragonborn has done her a favor in beginning the quest.
*From-Deepest-Fathoms will give the Lexicon to the Dragonborn even if they are in the water and not on the docks.
*If any Dwemer weapons, such as the Dwarven bolt, are taken, a letter will be sent from Calcelmo through a Courier stating he wants the Dragonborn to bring one to him in return for a large payment. This will begin the quest "Buy Dwarven artifact."
*It is easy to become stuck in the southeast corner of the room in which the apparitions discuss whether the Dwarven automatons were sleeping or waiting.
==Trivia==
*There are some references to William Blake's The Marriage of Heaven and Hell:
**The text of The Marriage of Heaven and Hell specifically deals with ancient and forbidden knowledge.
**Blake describes hanging over a pit of spiders in his work said to be a vision of Hell, an image similar to skeleton over the pit in Avanchnzel, with four spiders at the bottom.
*Quest objective 10 does not hyphenate the name "From-Deepest-Fathoms" despite the hyphenated form being correct and used in all other contexts.
*If the quest reward is combined with the Warrior Stone, Smithing will increase 35% faster.
==Bugs==
* Not necessarily a bug, but occasionally, when swimming near the docks in Riften, you will be addressed by From-Deepest-Fathoms, who angrily asks why you are bothering her. However, in the subtitles, her name only shows up as Fathom.
*There is a rare chance that in the Avanchnzel Boilery's first ghost encounter, From-Deepest-Fathoms will not say the last line in the conversation and the ghosts do not vanish. When the next few ghosts appear, they do not say or do anything and stay put. This does not affect the quest, but it's also interesting to note that the Dwarven Centurion ghosts show up as enemies on the compass and the real Centurion cannot walk through them.
*After reaching the end of Avanchzel, it might be impossible to place the Lexicom.
* Saving before entering the Boilery is advised as it is prone to glitch and lock up while in the loading screen.
*Whilst in the Boilery there is a chance that a Dwarven Spider will spawn under the grated floor in one of the corridors, but it cannot hurt you and vice versa. However, it may stop you from clearing the ruins. To fix this simply open up the console and type killall whilst standing above it, or by using Blizzard while standing directly above it. Another way to easily kill it is using Chain Lightning.
**Using a wooden plate, it is possible to glitch through one of the lower walls to kill the Spider.
**Certain spells and shouts, such as Fire Breath and Flaming Familiar, can go through the gaps in the grates on either side by the pillars and hit the spider.
* When entering the first room with the Dwemer Spiders and attacking with bow and arrow, the arrows pass straight through them and they receive no damage.
* In the room where they talk about how they should have hired a thief are multiple enemies. If you run up close to the ghosts and start fighting those automatons the ghosts may react like characters when they notice a fight nearby (e.g. "I'm getting out of here").
==Appearances==
*
de:Unergründliche Tiefen
es:Simas insondables
ru:Из глубин
Category:Skyrim: Riften Quests
Category:Skyrim: Side Quests