Greger's Grotto

Somewhere in your campaign world there is a rugged,
isolated coastline. Along that coastline are a series of natural
caverns. In those caverns live a small community of pirates
and outlaws: Greger’s Grotto.
The main feature of Greger’s Grotto is a large underwater
cave, where less-than-legal ships can moor out of sight of
navies and coastguards. Here they can trade in stolen and
illegal wares and stock up on provisions. All for a small fee,
of course.
The other attraction of Greger’s Grotto is the arena. Like
anyone, bandits and thieves desire entertainment. For
generations the Greger family has turned a profit by buying
slaves and beasts and setting them on one another in the
arena. These bloodsports don’t turn a direct profit, but they
do encourage the Grotto’s lawless visitors to stay longer or
return more frequently than they might otherwise. And more
visitors means more fees.
The PC are the newest lot of slaves forced to fight in the
arena. Can they survive the arena combat, and the harsh
prison lifestyle? Will they ultimately be able to escape?