“ 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...”
“ Anything not bolted down has a chance of moving about when unobserved. The items are smart enough to open simple latches, or break weak bindings. The rate of this oddness seems to follow certain astrological patterns.”
“ Every now and again, the region encounters a dense blue fog. Every now and again, things disappear into the fog never to be seen again and things appear out of it from other places or world. It seems the fog is the material form of some minor diety charged with moving things around the universe to balance cosmic forces.”
