Thirty slaves, some of which have hellish lives of toil, others which have a somewhat easier life.
After Buddha died, his shadow was still shown for centuries in a cave—a tremendous, gruesome shadow. God is dead; but given the way of man, there may still be caves for thousands of years in which his shadow will be shown. And we—we still have to vanquish his shadow, too.
Come hither peasant!
A casual remark by one of the party about something met on a previous adventure leads to a summons to and grilling by the Mages' Guild (or equivalent), probably resulting in an expedition back to that area to recover the things for 'study' by the Guild. The party's presence will be 'requested' for this expedition.