The Staff of Magnus (Skyrim)

Part one (Mzulft)
Mzulft

Part Two (Labyrinthian)
Upon arriving back from Mzulft, you find Ancano in the room with the Eye of Magnus. He is keeping everyone out with a shield and doing something with the Eye. Upon trying to stop him, Savos Aren is killed, and you are tasked to find the Staff of Magnus from the Labyrinthian to put an end to whatever Ancano is doing.

Labyrinthian

Upon arriving at the Labyrinthian, the staircase the right leads to a large stone door. Opening this door requires the Torq of Labyrinthian obtained from Savos Aren's Death.

Here you see what appears to be a remanant memory of the place. You can see the mages of the college all discussing entering the Labyrinthian. After watching them talk, go into the next room, where you will see a lever and iron bars. On the other side are several skeletons and a Skeletal Dragon (note, this dragon does not have a soul to absorb). If you have problems with this part, know that you can shoot through the iron bar door if you stand right next to it, and they cannot shoot back.

After this room is another vision, describing their encounter with the dragon the first time around. Standing in the hall is an Etched Tablet which reads:

"Hail All - Brave City Bromjunaar Forever These Walls Shall Stand May Enemies See Her Majesty May all Quake to Behold Her"

The next room holds a frozen door and two guardians. A voice speaks to you before entering the room, which drains you of all your mana, but does not hurt. To pass, you must melt the door with Flames. If you do not have this spell, there is a book to teach you it in the same room.

Down the path a little ways is a room guarded by two Drugar Wights. A Door Sealed with a Lightning Rune lies behind them. This rune does approximately 100 pts of lightning damage, and wards do not protect against any of it. In this room is a spell book for Equilibrium which turns 25 pts of life into mana per second.

At the bottom lies a river. Follow it through several doors (along the way you should find 4 malachite ores in a pool/side area of one of the halls.

A large metal bar gate stands on the other side of a room, pull the lever to continue. On the otherside, three wisps float around a fire and stones. They are non-hostile until you run past them. After defeating the Wispmother, continue to a door which is on fire. Use frost magic on the door to put it out.