Ophidian Monastery

From publisher blurb: Ophidian Monastery is a Fifth Edition plug-in adventure for four characters with an average party level (APL) of 11, 14, 17, or 20. This document offers details for each level and makes adjustments accordingly. While they are traveling—or trapped—on the plane of elemental chaos, the characters must enter an ancient monastery. The monastery is home to a race of dangerous snake-humanoids called ophidians.