Rotblack Sludge, or The Shadow King's Lost Heir
An introductory dungeon crawl. The PCs face execution for heretical theft until a masked Seer — a Courtier of the Shadow King — offers a chance at life. The King's one true heir, his son Aldon, is missing. Without an heir the throne will pass to his imbecile brother. Retrieve Aldon discreetly from the Accursed Den and wealth, life, and freedom will be yours.
The Seer scries the Den and tells two truths. The Seer's d8 of things he might see mixes truths and lies. Some confirmed: a glass-house cult leader (true); cannibals (true); a vast intestine-creature in the depths (true — the Gutworm); Aldon may be unwilling to leave (true). Some lies: gases that drive intruders mad (false); blood-touched lamp oil (largely untrue); an ancient man to fear and avoid (false).
15 rooms of the Accursed Den plus the lethal Rotblack Sludge flooding its lower chambers. Random encounters from two tables: violent (gnoums, mongrels, sharp-toothed guards, Nesting Death spider) and once-per-scenario weird (Distraught Spirit who pleads with PCs to end the Gutworm; Sagsobuth the interdimensional trader; sudden silence; teleporting sarcophagus).
Major NPCs: Fletcher (cannibal warlock who rules the Den), Lesdy (who reads alone in the Greenhouse and seeks to turn the Gutworm against him), Aldon (pudgy, arrogant, eating bones), and a chorus of bewildered guards, mad prisoners, and forgotten skeletons. The King Lenard II statue conceals a passage to Aldon by way of an eye.
Shadow King, Accursed Den, Aldon, Fletcher, Lesdy, Gutworm, Rotblack Sludge, Sagsobuth, Tired Crystal Demon, King Lenard II, Nesting Death, Dusk Gnoum, Mongrel, Goblin
The Seer's identity is unnamed. The "ancient man" he warns is fictitious — but a GM could place such a man for paranoid players. The deep caves beneath the Sludge — Lesdy's goal — are wide open expansion territory.