Breadcrumbs:
Still no walkthrough but I have a funny story about this one. I was having so much trouble getting Silent Assassin on this one that I thought I would bring the crossbow into one of the upper rooms above the plaza and try to take out the downstairs assassin with it. I figured maybe that would make the difference. Well, it didn't but can you imagine sneaking through the streets in my assassin costume carrying a crossbow without causing any alerts or close calls? I ended up figuring it out but I thought it was pretty good that I was able to get the crossbow into one of the upper rooms.

