Wytchwolde-Under-Ash, once a great Thorpe, was razed to the ground by the ruthless, and truth told more than slightly deranged, Porcelain Princess and her henchmen, the Purifiers. When the flames had at last subsided, and a kaleidoscope of swirling, dull-gray ash choked the sky, nine hundred acres of old growth iron spruce, black larch and weeping birch, was burned to utter cinders, along with the entire coven of witches comprising the Sisterhood of the Silver Teat.
Now, centuries later, the forests are somewhat re-grown, and the town of Foolswater stands where Wytchwolde-Under-Ash once did. It is said that even to this day, one can still find ashes in the otherwise potable well-water of this village. Once a year during the Winter Solstice, the “Ash-Wind” comes to Foolswater, a suffocating black cloud that passes quickly but leaves dead birds and animals in its wake, darkening the trees, and staining the sky with black snow. The inhabitants of the village know better than to be caught outside during the day-long Ash-Wind. Everyone is locked snugly inside, singing old hymns that curse and re-curse the burned witches who once called this place home.
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?
Near a major city, a mirror image of the place has appeared. This strange double is infested with hostile insectoid humanoids that appear to match the city folk in numbers and armaments. The humans’ diviners have determined that the secret of the city’s appearance can be found within the double’s college of magic, so heroes are needed to explore within this mirror city and discover what has drawn it from its distant realm. There isn’t much time to spare, as the bug folk find their mammalian counterparts unnatural and blasphemous, and plan to destroy them.