The soul of a mage has been trapped in his own bust for centuries. The bust is a foot in height and made of a dark silvery metal. It is well crafted, perfect in every detail of the mage's features. The frozen expression is one of shock. It was sold off in auction after the mage's unexplained disappearance and has been passed around as a curio ever since. The cause of his entrapment? He practiced in secret; none knew of his hobby. Being self taught, he was unable to tell that the spell he thought was for protection was actually for entrapment...
A plague has hit the local area.
In humans it affects only the most vulnerable, the children and the very old, and even than it's little more than a summer cold. 24 hours of sniffles and then it's gone, barely noticeable really.
To sheep however it is fatal and the whole economy of the area is in serious trouble. If this keeps up the area could well be facing famine.
Somebody (enter the PCs) must find the rare herbs needed to make a cure.