The Knight's Well
"There is a fine stone Well in the Courtyard of the Monastary." Lort Arno rubbed his finger beneath his itchy nose. "My spies have seen the Abbot go to it every morning with a heavy bucket and having lowered the bucket down the Well, come away with a bucket much lighter, yet filled with water."
"I want you to scale the Monastary wall sometime past midnight and investigate the Well." Guildmaster Arno looks at you across the table. "If I am right, it is the only entrance to some otherwise inacessible Dungeon."
Down the Well
There is a fifty foot drop down the shaft (overlooked by engraved stone faces which can be climbed as footholds) to water, but there is a secret door thirty feet down that can be opened by triggering a release in an eysocket of a stone face above the door.
Beyond the Door
There is a chamber here with racks of kitchen implements and pots. It connects to a network of old subterranean barracks where cultists, outlawed on pain of death in these parts, hide.