Did we miss anything in this section? Is there something we didn't discover? Let us know!

Background

You'll receive this quest immediately after completing the quest Trinity Restored.


Walkthrough

For this quest you'll need to travel to Irkngthand (located in the mountains to the northeast of Whiterun) so you can meet up with Brynjolf and Karliah and hunt for Mercer Frey. When you reach the ruins, you'll find the place overrun by bandits, including a bandit chief. To get inside, you'll need to climb upwards, eventually ascending several wooden ramps leading to the entrance.

Inside Irkngthand, you'll discover lots of dead bandits and destroyed automatons, implying that somebody beat you there. You'll also encounter some surviving automatons, who won't be happy to see you, plus some traps, such as the fire spouts near the exit from the Arcanex (#1).

You'll catch up with Brynjolf and Karliah at the start of the Grand Cavern (#2). Karliah will inform you that Mercer is somewhere up ahead, and she'll warn you to be watchful for any "surprises" that he might have left behind. Then Brynjolf and Karliah will start following you.

As you progress through the Irkngthand Grand Cavern and Slave Pens, you'll spot evidence of Frey a couple of times (at #3 and #7), and you'll battle lots of falmer. Eventually, you'll reach the Sanctuary (#10), and you'll witness Frey stealing the Eyes of the Falmer from a giant statue. After a bit of banter, Frey will force Brynjolf to start attacking Karliah, which will leave it up to you to battle Frey.

Frey dual wields daggers, but he's tricky. He'll alternate between attacking you and turning invisible and running away. If you have any way of casting Detect Life (such as the scrolls from #7), then you can keep track of Frey's position and continue to attack him. Otherwise you'll just have to wait for him to show himself. Aside from the invisibility, Frey is just a regular melee boss, and you won't need to do anything complicated to defeat him.

When Frey dies, he'll drop the Skeleton Key, the Left Eye of the Falmer, the Right Eye of the Falmer, and a lot more. But at the same time, the Sanctuary will start filling with water, and you'll need to find a way to escape. This is pretty simple. You'll just need to wait for the water to rise high enough, at which point a section of the wall behind the giant statue's head will collapse, revealing an exit tunnel. When you go through the tunnel, you'll end up in Bronze Water Cave.

To complete the quest, you'll need to talk to Karliah in the Bronze Water Cave. She'll reward you with a Nightingale Bow, a leveled item. You'll get the best version of it if you're at least level 46. Karliah will also encourage you to return the Skeleton Key to the Twilight Sepulcher, but she'll warn you that Nightingales no longer have free access to the sepulcher's inner sanctum, and so you'll have to survive the Pilgrim's Path, a "test of worthiness," to put the key back where it belongs.

Note: When you talk to Karliah, you'll be able to ask her about Agents of Stealth, Agents of Subterfuge, and Agents of Strife. These are options you'll get from Nocturnal when you return the Skeleton Key.

Another Note: The Skeleton Key is an unbreakable Lockpick, so you might want to take advantage of it for a while before handing it over to Nocturnal.


1 - Fire Spout Traps


2 - Brynjolf and Karliah


3 - Balcony

When you reach the balcony here, you'll spot Frey in the distance heading towards the Slave Pens (Exit B).


4 - Ballista

If you activate the lever next to the ballista, then you'll shoot a bolt at the falmer camp below, and perhaps take out one of the falmer.


5 - Levers


6 - Gate

To open this gate, you'll need to activate the two levers on the ledges above you (#5). The levers will only move the gears for a short period of time, so you'll have to activate one lever and then immediately run over and activate the other one.


7 - Looted Treasure Room

Inside this room you'll discover three empty chests, all pillaged by Mercer (as evidenced by the "One step ahead -- Mercer" message written backwards over one of the chests). However, you will find two Scrolls of Detect Life, which might come in handy later.


8 - Dwarven Centurion

You'll find a dwarven centurion (of some sort) stationed here. If you press the button on the side of the entrance staircase to the northwest, then the centurion will wake up and attack whatever it sees, including the falmer in the room.


9 - Torture Chamber

You'll encounter a couple of falmer in this room. If you want to, you can pull the lever on the ledge overlooking them, which will turn on a blade trap and kill them. A dead thief in the room will have Thief's Last Words in his inventory.


10 - Sanctuary


Exits:

1. Elevator between the Arcanex and the Grand Cavern.
2. Doorway between the Grand Cavern and the Slave Pens.
23. World exit.