A small, primitive village has yet to discover fire, which is a good thing because there are highly flammable (but not otherwise dangerous) gasses in the air. The heroes, blissful in their ignorance, don't know that and think it a wonderful idea to show the locals open flame.
Unbeknownest to the character, he is in the royal bllodline. Suddenly the majority of royals fall ill and die, and the hero is left with the crown, but no experience or idea of what to do.
A Deity of some sort has unleashed a plague of bookworms or something like that in the area. Almost all spellbooks are destroyed, along with bardic and historical books.
Culture/Religion: based on fear and respect. Gods are very dangerous creatures, sometimes friendly, often not. Temples are the way to make contact with them... if not easier, then at least more concentrated in one place. Were it not for the temples, gods could be running amok among the people. Therefore, mortals have to keep the gods close to temples, entertained and worshipped. It doesn't make the bad ones any friendlier, though (and is no guarantee some won't go on trips now and then). Still, there have to be priests that are hardy men, able to survive the rigours of their position, get a sufficient number of worshippers to make the gods feel important enough, and mediate the contact between mortals and immortals.