Darkness Falls

It is the year of Our Lord 1293.
Assistant to the Royal Architect, Tynon Wade, is charged by Edward I to investigate what is happening in the South Wales township of Rhaeadr Tywyllwch which is living under a threat that comes under the cover of night. It preys on anyone who lights the darkness, it swoops upon them leaving them as piles of ash.
Could the rumours be true? That the Red Dragon of Wales has returned?
If it has, can it possibly become the weapon the Welsh need to rise up and defeat their English oppressors?