The Secret Compromised

This is a quest involved in the Black Temple Attunement Chain:

The Black Temple attunement starts at The Altar of the Sha'tar for Aldors, and the Sanctum of the Sun for Scryers. Both are in Shadowmoon Valley.

Aldors start attunement from Anchorite Ceyla (http://www.wowhead.com/?npc=21402) at the Altar of Sha'tar in Shadowmoon Valley:
1. [A] http://www.wowhead.com/?quest=10568 [70] Tablets of Baa'ri
2. [A] http://www.wowhead.com/?quest=10571 [70] Oronu the Elder
3. [A] http://www.wowhead.com/?quest=10574 [70] The Ashtongue Corruptors
4. [A] http://www.wowhead.com/?quest=10575 [70] The Warden's Cage

Scyers start attunement from Arcanist Thelis (http://www.wowhead.com/?npc=21955) at the Sanctum of Stars:
1. [Sc] http://www.wowhead.com/?quest=10683 [70] Tablets of Baa'ri
2. [Sc] http://www.wowhead.com/?quest=10684 [70] Oronu the Elder
3. [Sc] http://www.wowhead.com/?quest=10685 [70] The Ashtongue Corruptors
4. [Sc] http://www.wowhead.com/?quest=10686 [70] The Warden's Cage

After that, the chain comes together for Aldor and Scryer.

5. http://www.wowhead.com/?quest=10622 [70] Proof of Allegiance
6. http://www.wowhead.com/?quest=10628 [70] Akama
7. http://www.wowhead.com/?quest=10705 [70] Seer Udalo

Seer Udalo is found in the Arcatraz (http://www.wowhead.com/?zone=3846) just before the last boss.

8. http://www.wowhead.com/?quest=10706 [70] A Mysterious Portent
9. http://www.wowhead.com/?quest=10707 [70] The Ata'mal Terrace
10. http://www.wowhead.com/?quest=10708 [70] Akama's Promise

After you finish this chain, you get to pick from some rewards and the chain seems like it ends. It continues however, inside Serpentshrine Cavern (http://www.wowhead.com/?zone=3607) from an NPC called Seer Olum (http://www.wowhead.com/?npc=22820) who you can speak with after killing Fathom-Lord Karathress. He starts the next part of the Black Temple Chain by offering the quest:

1. http://www.wowhead.com/?quest=10944 [70] The Secret Compromised
For this quest you just return to Akama.
2. http://www.wowhead.com/?quest=10946 [70] Ruse of the Ashtongue
In this quest, you must use the costume Akama provides, and kill A'lar in Tempest Keep: The Eye while wearing the Ashtongue Cowl. Attunement for The Eye is a whole different chain.
3. http://www.wowhead.com/?quest=10947 [70] An Artifact From the Past
In this, you need to gain access to The Battle of Mount Hyjal in Caverns of Time, and slay the first boss, Rage Winterchill. Attunement for this involves killing Lady Vashj and Kael'Thas Sunstrider.
4. http://www.wowhead.com/?quest=10948 [70] The Hostage Soul
For this you must speak with A'dal in Shattrath city.
5. http://www.wowhead.com/?quest=10949 [70] Entry into the Black Temple
For this, just speak with the naaru Xi'ri in front of Black Temple.
6. http://www.wowhead.com/?quest=10985 [70] A Distraction for Akama
Unknown what this quest asks of you, most likely you need to defend Xi'ri and make your way into Black Temple. At the end, you become attuned to enter and are granted The Medallion of Karabor (http://www.wowhead.com/?item=32649)

At this point, you are attuned and can enter Black Temple, although the chain continues and you can soon upgrade your medallion. It continues with:

1. http://www.wowhead.com/?quest=10958 [70] Seek Out the Ashtongue
You just need to find Seer Kanai (http://www.wowhead.com/?npc=23158) inside Black Temple.
2. http://www.wowhead.com/?quest=10957 [70] Redemption of the Ashtongue
This involves entering Black Temple, and killing the boss the Shade of Akama (http://www.wowhead.com/?npc=22841).
3. http://www.wowhead.com/?quest=10959 [70] The Fall of the Betrayer
After killing the Shade of Akama and returning to Seer Kanai, he asks one last thing of you. Kill Illidan The Betrayer. After doing so, you are granted the Blessed Medallion of Karabor, an upgraded version of your original medallion, and allows teleportation to the Black Temple.

The process of attunement to the Black Temple begins in Shadowmoon Valley with a very long quest chain that requires trips to the Arcatraz, Serpentshrine Cavern, Mount Hyjal and finally the doorstep of the Black Temple itself. Even if you're not planning on raiding just yet, the chain does offer some nice blue rewards half way through. It starts differently depending on whether you're Aldor (A) or Scryer (S):

Aldors pick up the line from Anchorite Ceyla in the Altar of Sha'tar:
1. (A) [70] Tablets of Baa'ri
2. (A) [70] Oronu the Elder
3. (A) [70] The Ashtongue Corruptors
4. (A) [70] The Warden's Cage

Scyers get it from Arcanist Thelis at the Sanctum of Stars:
1. (S) [70] Tablets of Baa'ri
2. (S) [70] Oronu the Elder
3. (S) [70] The Ashtongue Corruptors
4. (S) [70] The Warden's Cage

At this point the chains converge for both factions:
5. [70] Proof of Allegiance
6. [70] Akama
7. [70] Seer Udalo (Dungeon)

Here, you have to venture into the Arcatraz (which requires a Rogue with 350 lockpicking or somebody to open the door who's completed the Arcatraz Key chain, which requires trips to the Mechanar and the Botanica respectively) to the room just before the final boss. Sadly it's impossible to solo-stealth to. Finding Udalo leads to:

Talk to Akama:
8. [70] A Mysterious Portent
Kill waves of nonelites, 3 elites and a boss (5-man) on a terrace outside the Black Temple:
9. [70] The Ata'mal Terrace
Finally, deliver the medallion to A'dal in Shattrath City:
10. [70] Akama's Promise

The chain ends here, and you're granted a choice of rewards:
Akama's Sash (cloth DPS belt)
Bloodwarder's Rifle (gun)
Spellbreaker's Buckler (spelldamage shield)
Ashtongue Blade (phsyical DPS dagger)
Verdant Gloves (feral leather gloves)
Staff of the Ashtongue Deathsworn (healing staff)
However, if you now go into Serpentshrine Cavern and kill Karathress, you'll be able to talk to Seer Olum who'll continue the quest chain for you:

1. [70] The Secret Compromised
Go back to Warden's Cage in SMV and talk to Akama.
2. [70R] Ruse of the Ashtongue
Using the Ashtongue Cowl provided, kill Al'ar in Tempest Keep while disguised as a member of the Deathsworn.
3. [70R] An Artifact From the Past
You need to be attuned to Mount Hyjal for this. Simply kill Rage Winterchill and loot his phylactery (what is it with liches and their phylacteries?), then deliver it to Akama...
4. [70R] The Hostage Soul
...then return to Ad'al in Shattrath City...
5. [70R] Entry Into the Black Temple
...then go back to Shadowmoon and talk to Xi'ri on the road leading to the Black Temple. He'll ask you to help with
6. [70] A Distraction for Akama
...but once you tell Xi'ri you're ready (talk to him after accepting the quest), you can watch a scripted sequence that you do not actually have to help with in any way. After this is finished, talk to Xi'ri again for your Medallion of Karabor and the completion of Black Temple attunement. Congratulations, you can now waltz in to Illidan's latest bachelor pad!

But before you go, the chain continues from Xi'ri with:
7. [70R] Seek Out the Ashtongue
Time to start exploring the Black Temple! When you find the Deathsworn, they'll give you
2. [70R] Redemption of the Ashtongue
...which requires you to kill the Shade of Akama. Finally you're given
3. [70R] The Fall of the Betrayer
Yup, kill Illidan. No problem. Then you're done.

If you feel lost and unsure where you are in the chain, use the following copy-paste scripts:

[faction=932]
/run local y={568,571,574,575,622,628,705,706,707,708,944,946,947,948,949,985,958,957,959}print"The Aldor:"for i,q in ipairs(y)do q="10"..q print(i,"\124cffffff00\124Hquest:"..q.."\124h["..q.."]\124h\124r",IsQuestFlaggedCompleted(q)and YES or NO)end

[faction=934]
/run local y={683,684,685,686,622,628,705,706,707,708,944,946,947,948,949,985,958,957,959}print"The Scryers:"for i,q in ipairs(y)do q="10"..q print(i,"\124cffffff00\124Hquest:"..q.."\124h["..q.."]\124h\124r",IsQuestFlaggedCompleted(q)and YES or NO)end

Simply copy the script and paste in chat. You'll find a lot of text saying Yes/No for each quest in the chain, chronologically. Find the quest that isn't completed and look that up on Wowhead to proceed.

Have fun obtaining your [item=32757]