Leave the College, equip the Amulet you got from Mirabelle and we're off to Labyrinthian. Fast travel yourself to Morthal and from here, simply go southeast until you get to Labyrinthian. There are a LOT of Ice Trolls patrolling around Labyrinthian, by the way. They love to hang out here. Dual cast some fire to deal with them. When you get to the entrance, you'll see some Spirit Forms of Savos and other members of the College...
Once the scene is over, approach the door and use the Torc of Labyrinthian to enter the place. In here, Savos' party appears once again. After the chat, check the northeast table to find the Spell Tome: Telekinesis . Go inside the next room and at the end of the hallway, there's a lever that raises some iron bars that lead into a room with a ton of skeletons (archers, mages and warriors) and when you step inside, a Skelletal Dragon appears! Yikes (and, very cool!).
The best thing before going inside is raise the bars, alert the skeletons so that they approach the door, then raise the bars once again and whack them when they're near you but can't reach you. You won't be able to defeat the archers this way, but you can deal with them after.
Once you're done with this area, continue east and Savos' party reappears. Now go out to the Chasm. In here, you'll arrive at a door sealed with ice. Kill the enemies that appear, grab the Spell Tome: Flames , learn it if you haven't (I don't think you can get this far without learning it!) and melt the ice blocking the door. In the next room, there are several Draugr.
There's a hall going south right under where you enter with a Draugr guarding it. Follow it, but beware of the trap on the door and kill the other Draugr inside. In here, there's an Alchemy Station and an Arcane Enchantment. There's also the Spell Tome: Equilibrium and a chest. Go back and continue downwards and now you'll see an entrance going west. Go through it, kill the Draugr, loot the place and go north following the lower path. When in the water, go left (N) and you'll hear the dragon tongue again You'll be drained of MP once more, but continue on and enter the door.
You'll fight a Skeleton and a Draugr here. Easy. There are two ways to go from here (they both lead to the same place). Lockpick the gate, loot the chests and pots and continue, dropping down the ledge. Cross the hall and in the next room, you'll find a Troll. Fun. Loot the chest on the south side and go north to the next room.
In this large room, you'll find some very easy enemies and a Troll on the left side after the bridge. Go through the cave where this Troll was and you'll find another Troll. Kill it, loot the place and go north. The voice appears once again. Now use the lever and go across. Be sure to grab the chest on the ramparts above you after you cross the spears.
You'll face a Fire Spirit up ahead. Use Dual Cast Frostbite to take care of it. Now use Frostbite on the door until it opens, watch another scene with Savos' party and proceed. You'll have to fight several Draugr Wrights here. They possess weapons that absorb either Stamina, HP or MP. Very nice weapons to have around.
Continue until you reach the next area of the dungeon. Follow the cave system while killing the Draugrs and the Spectral Dog and when you get to a double door going west loot the chest nearby and take the Spell Tome: Steadfast Ward from the stand. In the next room, you'll find several Soul Stones (soul gems). These are used against you to cast spells at you. Grab the first one on the right, then quickly run to the left to grab the second one. At the end, you'll see three tossing Fireballs at you.
Wait for the Fireballs to pass and quickly nab the stones. In the next room, kill the Draugr. You can also explore the tower above you as there's some chests up here. Heck, you can even find ores in the water below. Continue on and... your MP will be drained. Again. Dammit. When you get to a fork head south, lockpick the lock and grab the goodies. Continue on and in the next room, you'll have to fight a Draugr Deathlord . He's easy, but has a ton of HP.
As you proceed, your MP freaking goes down again. Also, some more enemies come out to play. Yay. Continue, listen to Savos, loot the place and continue through the double doors. Go ahead and do yourself a favor and save here, just in case. From the entrance, you'll see two beams of light joining together on the right side. First of all, go to where these two beams of light are coming from and kill both sorcerers .
When you kill both sorcerers, the true nightmare begins: Morokei awakens . This guy is a DRAGON PRIEST , and can likely kill you in 2-3 hits if you aren't careful, so there's no way you can face him face to face unless you're a badass (and you may very well be, who knows!).
With that in mind, you're going to want to use this area to kill him, sniping down at him from above with arrows or magic until he dies and taking cover to heal when need be. use the pillars to give yourself cover and to be able to go back and forth between them quickly. This will often make Morokei hit the pillars while you hit him.
Depending on your strength, this can take awhile (5+ minutes) but it's the safest way. PLUS you can always chicken out and use the pillars to heal. Also, don't be afraid to use potions! Moments like these is why you are carrying them around!
After the fight, loot Morokei for the Staff of Magnus and the Morokei Mask (magicka regenerates 100% faster). These are wonderful items! Follow the east path on the higher level and follow the path until you meet Estormo. Kill him and proceed until you reach the world map once again. Fast travel back to the College . Speak to Tolfdir and the quest comes to an end.