From the introduction: You’ve come to the wild frontier outpost of Ylraphon, a town rebuilt from destruction and now ruled by adventurers, to pass on a proud noblewoman’s final wish to her dungeon-raiding heirs. Yet the young heroes of House Marsh have delved too deep. Can you rescue them from a trap-filled ruin, vengeful assassins, and a mysterious entity that turns its attackers into its defenders? A 4-hour adventure for 5th-10th level characters (optimized for 8th-level).