Those fancy robes are not just for show.
The teeth and fingerbones of holy men and more
The Pool of (add the name of the God or Goddess of your choice) is well known as one of the greatest holy places of the world. It is said to be full of piles of gold and jewels, a place where wishes are granted, wounds are healed, prophets have dreams that come true, and suspected criminals are fairly judged. Pilgrims from the other end of the world have been known to travel for more then a year, braving the perils of disease, brigands and bad weather, just to reach it's holy waters.
The characters are given the task of transporting a flask of highly volatile liquid a long distance. The flask cannot be shaken too much or it will explode. The adventure involves stormy sea-voyages, bumpy cart rides through densely populated towns and horseback combat. In short there are many opportunities for it to break and explode.