From the introduction:
A solar eclipse approaches, and a fiend plots to give the Moonlit King a foothold in Midgard. Recently, a meteorite fell in the hills near Lake Jingar in the Rothenian Plains. A collection of druids hailing from across the plains made a pilgrimage to the crash site to investigate the auspicious omen. Seeing an opportunity to curry favor with the Moonlit King, a lunar devil called Palus stalked the assembly and began to twist the minds of the fearful druids. Under the fiend’s influence, the druids banded together to form a lunar circle intent on drawing in the moon’s power. The circle erected a compound around the meteorite crash site and now unknowingly prepares a ritual that will tear open a gate to the deadly Shadow Realm.