Note: Must complete the mission 'A New Source of Stalhrim' for this quest to become available.
Look for a historian by the name of Tharstan in the Skaal Village will ask the Dragonborn to help him explore a tomb. After the conversation is over, the quest will begin and Tharstan will head off to Vahlok’s Tomb .
Enter the tomb and talk to Tharstan. Next, walk down a short pathway towards an etched tablet overlooking a trapdoor fire pit. Below the tablet is a handle. To the left and right are paths that lead to other sections of the tomb.
To solve the riddle, drag a corpse of a nearby Draugr onto the trapdoor and pull the handle located under the etched table to provide a sacrifice. This will open two routes off of the platform, marked by torches.
Retrieve the first key
First head over the left bridge and through the tunnels deeper into the ruin. Defeat the various Draugrs found here and at the end of the tunnel pull the chain to open the gate to the next room. Through this door will be a glowing monolith, with a bow, a sword, and a staff in front of the three different faces of the monolith.
In order to unlock the way out of the room, the glowing stones corresponding to each of the faces of the central monolith must be struck with the category of weaponry provided on that face of the monolith - i.e. sword strike for sword side, etc. Any weapons can be used and a fire spell can be used in place of the staff. Once all three glowing stones are activated, the gate to the next room will open.
Continue through and defeat the various Draugrs that burst out of coffins. After defeating the Draugr Deathlord, search it for the Amethyst Claw, Left Half. A Dragon Shout Wall is in the back of the room, providing the first word of the shout Battle Fury . Take a left through the tunnels and pull the chain on the wall the get back to the central cavern with the fire pit.
Retrieve the Second Key
Next head over to the right hand side bridge and continue across to the far side of the cave, following the path lit with torches. In the next room are nine stone squares on a raised platform, so to solve the puzzle, starting at the bottom left and walk in a zig-zag pattern along all the panels ending up on the top right panel.
If done correctly, the spears blocking the next room will retract. This room contains several Draugr and another Draugr Deathlord. After they have been defeated, search the Deathlord’s body for the Amethyst Claw, Right Half. The second word for the shout Battle Fury is in that room.
Like before, head through the shortcut back to the main chamber. Insert the Amethyst claw halfs into the keyholes on the central platform. The gate should open, leading to another inscription and a handle.
Turning the handle activates a series of magical platforms which act as a bridge to reach the far side of the chamber. Each panel will disappear after a short period of time, so in order to prevent falling, travel across quickly, stepping onto the furthest available panel. Once the far side has been reached, a solid path of panels form, leading back to the first platform.
The next three bridge section of the ruin are much the same. Pull the handle and activate the moving bridge. Each bridge will move slightly faster than the last. In the canals below are several Corrupted Shades that will attack anyone that falls down to them. After crossing all of them, open the iron door to reach a long hall with a Dragon Claw combination door at the end.
The combination is Hawk - Wolf - Dragon , which does not appear on the claw. Once the door opens, head up the stairs and into the main burial chamber where Vahlok the Jailer rests. The third word wall for Battle Fury is also found in this chamber, along with a small amount of leveled loot in the boss level chest.
Vahlok the Jailer Boss Battle
Approaching his sarcophagus will cause him to awaken and attack. As battle begins he will summon a Flame Atronach and activate his Flame Cloak. During battle he uses fire based Destruction spells, including Firebolt, Incinerate and Flames. In addition, around the room are several pressure plates that shoot jets of fire when stood upon.
Once Vahlok is defeated, talk to Tharstan who will pay 1,000 gold for escorting him through the dungeon, completing the quest.