From Introduction:
Summary
The Shrine of the Deep Prince is an encounter site for a Renassiance fantasy setting. Certain story elements are keyed to the adventure: The Prison of Abazad, however, the story is mutable as needed. The setting for the site is heavily influenced by the sea, thus should remain in a port town or seaside setting.
Encounter Summary: Following the trail of the Purple Sapphire, and the nefarious thief Bittersnail, the group finds a little known shrine in an out-of-the-way alley in the Bleakshore district. The secret of the shrine reveals a hidden chapel and cult dedicated to the vile demon-god Dagon. Even if they prevent the foul ritual of the True Servant, a Dagon-spawned horror emerges and rampages to through the seaside port of Greenstone.