An ancient people built mystical fortresses made of melted stone; from the wall’s these fortresses defenders appeared to burn with a powerful energy and strike at their opponents with a supernatural force. Today most of these forts are abandoned and the art that made them lost.
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.