The group had defeated the “abbot,” which was a galbrezu demon in disguise, during the last session.
The group moved to the second story of the monastery and quickly encountered four guards and a witch, Haetna Dubless. Despite her hexes, polymorphing Cy into a bunny, and her lightning bolts, she was quickly felled and the remaining guards fled. Blodwin was able to dispell the polymorph and Cy returned to normal.
In the library they found the reconstructed skeleton of Ootha, the hag leader of the witch coven. As Stephan tried to rip it apart, the four guardian invisible stalkers attacked — the fight was horribly drawn out, but in the end the guardians were killed and the skeleton was disassembled and put into the bag of holding. The remainder of the 2nd floor interior was investigated with no further incident or clues.