During certain years, people in Akgku claim to observe a green flame coming from the sea and erupting upward. It can be observed from a distance of two days’ journey or more. After burning for a considerable time, the flame disappears.
—Falklyde Wodinger, Haraconian scholar, in route to wondrous Udross and legendary Akgku.
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....)