“ Whale's Jaw is a crumbling stone monument that was once in the form of a skeletal whale. Many years have past since the construction of Whale's Jaw and these days all that can be seen in the 'jaw' jutting from the earth as if it is yearning for a final glimpse of sunlight before taking a plunge into the earth.
All around The Jaw are remains of oddly formed and weathered structures. They seem to have been smoothed and tumbled by severe rain or ocean currents. <em>Most say it is just another Wonder of The World, a mystery we will never know the answer to, but some know differently... I know differently...</em>”
“ With a huge number of sacrificial victims, another realm long ago secretly bound a Prince of the land spirits, Iorstonn by name, thus ensuring the fertility, and improving the magical defences, of their realm. But binding that Prince to one spot has disrupted the weather and magical patterns (ley lines?) over half the continent. Things have become bad enough that a coalition has been formed to rectify the situation, once divinations have established the cause.
Your party is one of the teams assembled to do the rectification: find the binding object and steal it ('so that we can destroy it here in our realm, of course'...*) or destroy it over there. Presumably the Prince will be grateful to his rescuers and angry at the binders, but with a greater spirit like Iorstonn one can never be sure: such beings are 'tricksy'.
* Of course, the rulers of our realm might want to control Iorstonn for their own ends...”