From publisher blurb:
Moonlight and Madness!
The famed observatory at Asteria Point has long endured upon its mountain heights, yet wars, plagues, and the ravages of time have dimmed its glory to a faint ember kept by a tiny order of faithful monks. When sinister forces stalk the night and even those faithful few begin to disappear, the church sends out a call for heroes to investigate and save this remnant of a wiser and more learned age. Yet all is not as it seems among the high peaks, and secrets grow darker and danger ever deeper with the moon’s every rising.
When Comes the Moon is a 5E adventure for 8th-level characters set in Yolbiac Vale, in the Lost Lands Campaign Setting. This rich and exciting world 20 years in the making has been home to dozens of adventures from Necromancer Games and Frog God Games and produced with their cooperation to be compatible with The World of the Lost Lands campaign guide! It is the second of six adventures in the Aegis of Empires Adventure Path, with each adventure exploring hitherto unexplored areas of the Lost Lands with a combination of horror, intrigue, deadly danger, and the lure of ancient mysteries.