"Reills. E'en the name makes me shudder. That there is unholy ground, cursed by most gods. Not even the demons and devils and the incarnations o' evil dare step foot there. Reills. You know me, I think money likes it in my pocket instead of wherever else it is. But, and I've heard rumors that say this, if theirs treasure on that ground, it ain't going in my pocket on pain o' death."
-Old Gerald, man in the pub.
You receive a vision of a rooftop "somewhere close by", where a rare moss grows; in the vision, you know the moss is suitable for greatly enhancing the effects of certain types of potions. Now go and find that rooftop. Don't fall off. (Of course, rooftop runners *will* be taken for miscreants by the local City Watch....)