Return to Karazhan: Cubic Cynosure

Never did legion but now you're going back and completing it?

-Enter "Return to Karazhan" in Deadwind Pass from portal over small bridge on tower to the right of the main entrance (looking at the entrance). (ie the Legion Kara, not the original)
-Go in, turn right, go up the stairs, and then anti-clockwise around the balcony,
-Go down stairs at end of balcony
-Go clockwise around lower balcony,
-Go down ramp and talk to man in front of curtain
-Start Opera Boss. STOP BE CAREFUL, some opera bosses are nukable and bug out which brick your progress thru the instance.
-Research on wow head the appropriate boss.
-Kill boss.
-Exit stage via other door, go around the back of the stage and underneath it, then up to the viewing area.
-Make your way to the stairs at the top of the map. (don't worry about the maiden boss).
-Go down the stairs and go and nuke Moroes on the level below.
-GRAB his keys.
-Go back up the stairs you just came down, follow the passage that takes you around the higher area looking down on the place you just walked thru twice.
-Follow that passage around to the "door" sign on you map. You should be just about where you came into the instance.
-Go up the decaying ramp, and keep going up as much as you can find. (lots of dilapidated ramps)
-Nuke the Curator
-Go thru the portal
-Run along upside down area
-Nuke shade of medihv
-jump down hole
-Get shrunk
-make your way down the pile of books.
-Nuke Mana devourer.
-Get unshrunk
-Loot the chest for the item.
-Hearth to legion dalaran .
-Turn in

edited for clarity from other feedback.

It's worth noting that this is not OLD Kara, it's NEW Kara.

Update: this can now be done using the LFG option. Choose Upper Karazhan. No attunement required when using LFG.

In case you are like me and came here to figure out which Karazhan dungeon you need, it's Upper Return to Karazhan.