Chase Beneath the Prison (Pathfinder)

From publisher blurb: A Pathfinder Mini-Dungeon for 3-5 characters of levels 16-17 In pursuit of a city’s kidnapped ruler, the adventurers find themselves investigating a former prison. At the bottom of an oubliette in the deserted rooms, they find a passage forced into the Underworld. Following a drow cult leader and warped ruler from the prison, the characters find themselves in a series of rancid caverns.