Key to Phantoms' Cloister

The annual haunting of a ghost in the streets of Loudwater is interrupted by a groundling attack. Their burrowing reveals a previously undiscovered reliquary containing a tangible shard of pure light. Following clues, the party makes their way to the ruin of Phantom's Cloister where they find Zhentarim battling cretures under the control of a vicious quasit.