1. Arcane Disturbances/Restless Activity - Beginning of the chain. Pick up these two quests outside of Karazhan from Archmage Alturus. It's in Deadwind Pass (just east of Darkshire). This part is soloable. Note that the Ghostly Essences have a very low drop rate, plus all the mobs are level 69-70 and very close together. Some classes may want to duo for this, for safety's sake.
2. Contact from Dalaran - Alturus at Karazhan instructs you to go to another mage in Dalaran, which is in Hillsbrad/Alterac Mountains. Also soloable.
3. Khadgar - You must go speak to Khadgar. He chills near the Naaru (A'dal) in the middle of Shattrath City. He gives you the first part of the chain that is group content.
4. Entry Into Karazhan - You need to go to the Shadow Labyrinth in Auchindoun and get an item there. This is the first Karazhan Key Fragment. To get into the Shadow Labyrinth, you'll need the key, which drops off of the last boss in Sethekk Halls. Many of us already have this key, and unlike the key to Karazhan, only one person in your group needs to have it for everyone to gain entrance to the instance (like UBRS). You'll find the first key fragment in an urn located to the left and slightly behind Murmur, the last boss in Shadow Labyrinth. You'll need to kill him to get it (he's really easy) and all players can loot the urn.
5. The Second and Third Fragments - For the next part of the chain, you must go to the Steamvault (in Coilfang Reservoir) and find the second key fragment. Jump to your right off the bridge that leads to the first boss. Swim down into the whirlpool-type thing and you'll find the urn near the bottom (kind of hard to see). Go to the Arcatraz (a 5-man dungeon in Tempest Keep in the Netherstorm) for the third key fragment. You'll need a key to get into the Arcatraz as well.
The Arcatraz key quest chain starts at Nether-stalker Khay'ji in Area 52. The first quest in the chain is Consortium Crystal Collection. You may have already done it, though, and will thus have to figure out where you are in the chain for yourself. Ultimately, you'll have to go to The Mechanar (Tempest Keep 5-man) and The Botanica (Tempest Keep 5-man) and obtain a drop from each of the final bosses of those instances. You take these two key shards back to Khay'ji, and he'll give you your Arcatraz Key.
Good job. You're almost there. Now you just need to actually go to the Arcatraz and get the third key fragment. It is located in the corner of a big blue room after the first boss. You don't even need to kill the first boss to get this key (but he's pretty easy, so you probably should).
Master's Touch - You're
almost done now. The final part of the chain involves completing the
Black Morass encounter in the Caverns of Time and talking to Medivh
at the end (you need to complete the "saving Thrall" encounter in
Old Hillsbrad Foothills before you attempt the Black Morass). This
is a tough encounter, but if you have a tight group and everyone
focuses, you can certainly get it done. Here are some tips on it:
Burning Crusade Guides