“ An example of a mythological worldview misinterpreting scientific practices occurred in Africa, where an aid organization, focusing on slowing and stabilizing population growth, distributed abacuses with red and white beads corresponding to a woman's menstrual cycle. Women were instructed to move one bead a day, only having intercourse on days represented by a white bead. However, the experiment failed, and the population grew in the households using the abacus. The women believed the abaci were magical, and that they would be protected from pregnancy by moving a white bead into the place of the red bead before intercourse.”
“ 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...”