Speaking With Silence

Speaking with Silence is the Thieves Guild quest which follows Scoundrel's Folly. It is offered by Mercer Frey immediately upon completion of the previous quest.

Overview

 * Prerequisite: Scoundrel's Folly
 * Quest Giver: Mercer Frey
 * Reward: N/A
 * Reputation Gain: N/A

Objectives

 * Meet Mercer Frey outside Snow Veil Sanctum
 * Enter Snow Veil Sanctum
 * Find Karliah
 * Speak to Karliah

Walkthrough

 * Meet Mercer outside Snow Veil Sanctum. Talk to him, and he will unlock the door. Enter it and cleave through the Draugr with him. There will be a Larceny Target on a trapped pressure plate, specifically the Model Ship which you can pick up and sell to Delvin for Septims, for somewhere around 300. At some point you will encounter a locked puzzle door, which usually requires a claw made out of a specific material (eg. Ivory Dragon Claw). However, this time Mercer will open it. Upon advancing after the locked door, you will be shot by a poisoned arrow, a cutscene will play and the screen will fade, afterthat you will wake up outside the Sanctum and you will will be confronted by Karliah, whom you and Mercer are looking for. Mercer will be gone. Speak to her, and find out about Mercer Frey's treachery to the guild.

Bugs

 * Sometimes Mercer Frey does not immediately unlock the door to Snow Veil Sanctum. This can sometimes be fixed by saving and reloading. Although that is not always the case. Pushing him with sprint may also work. It is unknown whether there are any fixes for this glitch. You cannot proceed further with the Thieves Guild if this quest it not completed.
 * If you've hit Mercer with an attack, he may go hostile on you. Simply sneaking away until the eye closes seems to fix it.
 * I walked up to the door and sneaked  took him good 25 sec to finally walk over to me and then he opended the door
 * I dont know if it affected achievements, but from what I read you cannot beat the game without beating this quest (bug where invincible Mercer follows you everywhere and in a later quest keeps fighting a dragon your supposed to kill). In your console type * movetoqt TG05 * then just walk toward the locked door. Fixed it perfectly. Typed with no asteriks of course. ***Update*** I had to use this command again on another glitched quest, and it has been the only console commands I've used. However I am still recieveing achievements, so it didn't disable them or have any affect on my game.
 * Note on above console command: Move away from the dungeon and have Mercer follow you until you're out of sight of the dungeon, then use the movetoqt TG05 command and it'll teleport Mercer to the door and have him unlock it. It does not seem to work if you're standing at the door and use the command while Mercer is in sight of the door.