From publisher blurb:
The party has either run afoul of the law or offended the local ruler such that they have summarily been tried, convicted, and sentenced to the favorite punishment of this province- death by being cast into the mysterious and ever-changing oubliette of the Minotaur, a seemingly endless labyrinth that lies beneath the city. Before being left to their fate, the oubliette’s sickly, hunched gatekeeper explains to them the extent of their punishmentonce they enter, leavings through the grated trapdoor to the oubliette will be impossible, but a massive, ancient gate just below may be unlocked from within if the condemned are able to retrieve the keys- all four of them. Only this way may the Party liberate themselves and, as is the law, be absolved of whatever offense landed them here- with a rumored treasure hoard on other side as a happy bonus. Of course, after several centuries of recorded use of this punishment, no one has managed to enter that gate and reclaim their freedom and prize. Downward the party is cast into the oubliette, provided only their personal equipment and meager supplies.