There are some types of evil that are not easily recognizable as such. Much like the mountain-top ascetic or the cloistered saint, there is no obvious sign of the darkness that lurks inside Vodai.
A family of semi-retired doomsday cultists, just trying to live a quiet life while tending an apple orchard in the country. Except with complications.
A village where everyone goes blind sometime during puberty. What could be causing this? Perhaps something in their diet. Or some malignant gene. How would an entire village where only young childen can see function?