Oblivion:A Plot Revealed

Quick Walkthrough
# Speak to Traven a few days after completing Information at a Price. He wants you to check up on the Bruma Mages Guild.
# Head to Bruma and go straight to the Mages Guild. The guild hall will be in flames once you enter.
# Fight your way through the ruins until you find Camilla Lollia. Kill her.
# Immediately after, J'skar will appear. Talk to him about what happened.
# Return to the Arcane University to report to Traven.

Detailed Walkthrough
A Septic Wound
Come back a few days after your last task from Traven and he will offer you another job that he does not have time to complete. You are to travel to Bruma and speak to Jeanne Frasoric there. He hasn't heard anything from her in a few days, and while he appreciates a break from her constant messages and questions, he is worried that this behavior isn't like her.

Something's Not Quite Right
When you arrive at the Bruma Mages Guild, you will quickly find that Traven's fears were correct. The place is in flaming ruins and overrun with undead. Selena Orania lies dead on the floor near the burning bookcase and Volanaro's lifeless corpse will be found sprawled on the stairs as you fight your way down into the living quarters, apparently slain as he tried to flee.  If the undead in the guild hall prove to be a little too much, or you lack the weapons to deal with them, just run outside and the Bruma Guards will provide some support (and if even they can't deal with the undead, attract the undead to the Fighters Guild next door and watch the show).

Upstairs, you'll find one necromancer, Camilla Lollia, apparently still looking for someone in the room. Allow her to say her piece then put her down; once she is dead, you'll be approached by the sole survivor, J'skar, who now appears in a corner of the room. He says he was invisible during the entire massacre (similar to his behavior in the Bruma Recommendation quest) frozen in terror, but claims to have seen everything including the arrival of Mannimarco. J'skar reports that Mannimarco slaughtered everyone&mdash;even draining people's souls&mdash;and then mentioned something about Echo Cave and destroying the Mages Guild. J'skar also thinks the King of Worms may have seen through his invisibility, stating that just before leaving, Mannimarco looked him in the eye and grinned, although why he was left alive he does not know.  The most likely possibility is that the King of Worms wanted J'skar alive in order to tell the Council of Mages about what had transpired.

Return Not So Triumphant
Return to Traven with bad news... again. He says he'll need at least two days to decide what the next step will be. Afterwards, speak with Raminus Polus to be promoted to the rank of Wizard.  He will also teach you the leveled spell Wizard's Fury.

Notes
After this quest, Volanaro is no longer available as a spell vendor. He is the only vendor in the game who sells the Summon Dremora Lord spell, so you may want to buy this spell beforehand. 
If you have the Spell Tomes official plug-in installed, you may still be able to find a Summon Dremora Lord tome.
Similarly, Selena Orania is no longer available as a vendor, so if you intend to invest in every store in the game, invest in her before beginning this quest. She is also the only vendor in the game who sells the Fortify Health spell, although other spells with the same effect can be bought from different vendors.
It is advisable to loot the Bruma Mages Guild building if you wish to and retrieve any items you have stored there there before beginning this quest, as all of the items will disappear once the building is destroyed. 
One item of particular value in the original building is the only guaranteed copy of the  Illusion skill book, The Wolf Queen, v 3. It is an orange book found in the southeast basement, first door on the right, lying on the desk.  This book will no longer be available after this quest has been started.
The Bruma Mages Guild is never repaired and stays in its ruined state throughout the game.
  An achievement will be unlocked upon being promoted to Wizard.
It is possible to jump over the burning bookshelf blocking access to the 2nd floor of the guild and bypass the basement entirely. But since J'skar will always go through the basement to exit the building, he will be attacked by the numerous wraiths down there on his way out, so it may be best to deal with them first before encountering him.
Technically, the members of the Bruma Mages Guild are not actually killed, but simply rendered inaccessible when the quest begins. The Bruma Mages Guild's interior will be swapped with a different set of interior cells that contain dead duplicates of the members, but the originals will remain alive and won't be disabled. Therefore, it is possible to "save" the guild members by moving them all to a distant location (using the Command Humanoid spell, Console commands, etc.) before A Plot Revealed begins so that they won't be in the building when the interior is replaced.

Bugs
 
 You can get around this by entering the console commands   and  .
 
 

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