Ok, I assume this is the quest for the spectre named Caracalla?
For me, I entered the house and had the dialogue with Caracalla. Then I proceeded to the barred gate on my right, lit both candles and saw the arrow pointing to my right. I went back to where I entered the house and I saw a huge X on the wall. On the left of the X, there is a small button you can press to 'fade' the wall away. Pull the lever in the newly discovered room and the barred gate will open.
Read the note left by the dead champion and take the key from his body. Head to the other door which hasn't been opened and discover another body. Read the note as it is important. Ok, on the left there is a room which has a barred gate and two candles. Light both candles (I don't know what effect it does, but heck just did it anyway). Now head on till you see 4 candles on both left and right sides of the wall, light them up and a passageway will appear.
Go on till you finish the boss fight. Step on the portal and you will be teleported to the room which was locked earlier on.
Inside there are 3 chests, you can lockpick 2 of them but Caracalla's chest is locked correct? So to unlock his chest, YOU MUST REMEMBER to TAKE the KEY from his burning corpse at Great Market Square where you first met him.
Oh and by the way, you need not teleport back to the boss room to get out. There is a button near the barred gate which opens it.
Edited by VictorTan86 (11/14/10 10:16 PM)