Ok, I'm at the end of the game and going back and trying to get the shrines finished. Early in the game I went and attempted to fight Umbra but got arrested while fleeing. Since then, I have never been able to find her. Now for the Shrine quest, the marker takes me to the Imperial City Temple and when I get there, the green arrow shows up in the Waterfront. Unless I can get outside the Imperial City walls, is there anything else I can do to finish this? It's the only Shrine I'm missing before the Hermaeus one.


Maybe a glitch to jump the boundaries of the Imperial City Temple?

If you are on a PC, you can use console commands to teleport her to your location. If you are on a console, I suggest you use the http://uesp.net/wiki/Oblivion:Exploitable_Glitches#Floating_Paint_Brushes and make a ladder over the walls. Then just fast travel out.