You can obtain this quest by visiting the ruins of Forelhost that are just south of Riften (on the southern side of the small mountain there). Outside there will be a man named Captain Valmir who will ask for you assistance in defeating a Dragon Priest that is believed to be in Forelhost and to obtain his mask. The quest will now begin.
Our objective is to of course obtain Rahgot’s mask. Optionally we are to find Skorm Snow-Strider’s journal. Head inside the stronghold and you’ll need to fight off a ghost right away! Loot what you can and head forwards (watch out for floor plates) and fight two more ghosts. The left path is gated, and the forward path is caved in so head right. Be sure to loot the room in front of you and then go right through the blade traps. Up ahead are two more ghosts, so take them out and search the table nearby for the optional journal.
After reading the book, grab the chest and go through the door. Continue on to see a path to the left (that has a chest) and a forge down below. Kill the ghost by the forge and loot this area for a LOT of metals. To the right is one more ghost to kill in a dining room. Check the side room, then head out into the large room with the walkway heading upwards. There is a ghost in here as well as TWO sleeping Draugr. Be sure to loot this place for a trapped chest up above as well as several gems lying on a table before going through the next wooden door to continue. Be careful of floor plates here. Kill the high level Draugr you find as well (let him cook himself if you want). There’s also a lever at the far end that unlocks a spike gate for a shortcut out, but go through the double wooden doors to continue into the crypt.
Now, the crypt holds a tricky decision right away. After killing the first ghost you find, you’ll see a path going LEFT and one going right. Now, we HAVE to go left, but it is LOCKED with a MASTER LOCK. Going right leads us to a chest with the KEY to that lock, but we still need to go left… So, if you can pick a master lock I’d say save yourself the trouble and do it. If you can’t, go right through the DRAUGR CATACOMBS. Go slowly, be careful of the "sleeping" Draugr (sneak attack them) and be EXTRA CAREFUL of all of the traps (which are all floor-plate traps… let the draugr use them on themselves if you can). At the end you’ll be in a room with a spiral staircase going up where you’ll have to kill a Draugr Wight Lord and two more Draugr. The key you need is in this room in a chest.
Either way, once you either pick the master lock or get the key, go to the caged well and jump in. Swim underwater to a cavern with three skeevers and a dead spider, then swim underwater some more to reach another area. Here you will find a LOT of poison as well as a RESTORATION SKILLBOOK called "The Exodus" on a nearby shelf. Through the next door is a battle, as THREE Draugr (high-level ones in my case) attack. The middle area of the floor also is a TRAP that raises you up into some spikes, so hang back and take the Draugr out safely before heading left and entering the Forelhost Refectory.
Head inwards and kill the two Draugr guarding the hallways. You’ll soon reach a dining room with two MORE Draugr (and another one up above, on the right). This room has a gated door in it, so go through the double wooden doors. Kill another Draugr guard and head right into a flowery area. Kill the three Draugr that attack here and read the note found in the left cubby. Oh, how sad! Sure enough, there’s small little bodies in this area. Grab the chest under the stairs and go up them. To the right is a lever that lifts the gate leading to the previous dining area.
Head into the alchemy lab now and kill two more Draugr. There are a lot of ingredients here as well as an interesting note. Move onwards to find an out of reach soulgem casting lightning at you. There is another Draugr here too, if the soul gem wasn’t bad enough. Stay out of its line-of-sight and run up to it after it attacks and grab it. The door to the right leads back to the dining room area, so go left and keep your eyes open on the right for the GLASS DRAGONCLAW on a pedestal. There’s an expert locked door nearby that should have at least one good thing in it as well as a master locked door that leads to the lightning soul gem (since you can grab it from the window, that locked door is worthless).
Continue onwards killing Draugr throughout the hallways until you reach a LONG hallway with a DRAGONCLAW door at the end. Line up the rings in this order:
- TOP RING: FOX - MIDDLE RING: OWL - BOTTOM RING: SNAKE
Use the keyhole to open the door, then save and get ready for a fight. I HIGHLY recommend you bring along some distraction: summons, call of valor, companions, WHATEVER. As you go up the stairs RAHGOT will come out to play. As you do so, however, FOUR Draugr will also appear BEHIND you. For us squishy types (mages, ranged) this surrounded nonsense is BAD news, so let your allies take the brunt of the attack and go backwards to regroup. Rahgot fights like every other Dragon Priest: POWERFUL magic attacks that can drop you in 2-3 hits easy. Use the room’s center pillar to give you breathing room if you need it and kill all the Draugr and Rahgot (being a ranger, I focus on Draugr first, THEN Rahgot). He’ll fall soon enough and give you his mask, which is also named Rahgot and increases your stamina by 70 if you wear it. Be sure to loot this area as well and then go out the double iron doors using the key you found on Rahgot.
Out here you can find a DRAGON WALL that will teach you LIGHTNING - STORM CALL. We have to return to Valmir now, so drop down and go see him (since we are RIGHT BY the entrance). You’ll learn that Valmir isn’t realy who he says he is and will have to kill him! You’ll be able to read his orders afterwards to see he was ordered to bring the mask to Labyrinthian. Once you have killed him though, your quest will be complete.