From the introduction:
A routine stop for the Adventurer's and their familes on a long caravan trip. A clifftop city, a city under siege, but no enemy is in sight. Locked doors and the shrieks of terrified people echo through the streets. Some run with knives and some are covered in blood. Your party turns to leave and finds they cannot.
Some arcane influence has trapped them inside the town. A voice whispers in the adventurer's minds, "Give me what I want and I'll go away" and suddenly the streets are filled with the mad and the insane, all begging for help against a presence that they cannot resist. In the distance, on a tall pyre, are the bodies of some of the townfolk's young.
Today is the day of the Sacrifice.
For characters of any experience level.