The Baronies of Erlkazar, once a prosperous region of pastoral tranquility, is now a land of nightmares and dread. Bandit armies plague the region, terrorizing the populace and surrounding countries of Calimshan, Tethyr, Amn, and Turmish. Though these threats are terrifying enough, it is nothing compared to what awaits the people of Erlkazar at night. In caves, tombs, and subterranean communities beneath the seemingly pastoral villages of Erlkazar live the secretive Night Barony. Ruled by the vampire Saestra and her legions of darkness, these monstrous denizens of the Five Baronies are the real power in the region. The country’s only hope of liberation is you.

"The Aboleth's Grotto" is a nihileth lair suitable for four 10th-level characters. The adventure can be completed in one session. The small town of Springwell harbors a secret that almost nobody knows about, and those who do conveniently ignore: it sights right over an unoccupied settlement of the deep caverns of the underworld.

Sarkt is an illithid sorcerer. It was cast out of its community for its heretical studies (Sarkt was in fact, lucky to escape alive). It didn't take the cunning creature long to pick up a few thralls and find a new place to live, safe from the murderous intentions of its companions. Sarkt dwells in the subterranean ruins of an ancient shrine to Blibdoolpoolp, the crustacean-headed deity of the kuo-toas. This shrine lies on the fringe of a region controlled by kuo-toas, but since Sarkt's arrival, the fishmen avoid the area. A few unfortunate kuo-toas now serve Sarkt as thralls and maintain the illusion that the shrine serves Blibdoolpoolp. Pgs. 82-88

TENTACLES. VERY DANGEROUS. YOU GO FIRST. Adventure in the Underdark, Part Two The colony of svirfneblin, while grateful for the adventurers’ deeds, is still in need of a reliable source of drinking water. The kuo-toa hold the lake, and there is the matter of the tentacled menace the party faced previously… This adventure is a continuation of Tentacles. Why Did It Have to Be Tentacles?, but can be run by itself as well. It is designed to easily fit into any standard fantasy setting. A 4-hour adventure for 6th-8th level characters

As a member of a bold party of adventurers, you and your associates have trekked far into what seems to be a whole underworld of subterranean tunnels -- arteries connecting endless caves and caverns which honeycomb the foundations of the lands beneath the sun. Your expedition has dogged the heels of the Dark Elves who caused great woe and then fled underground. This module can be played alone, as the conclusion to module D1 & D2: "Descent into the Depths of the Earth," or as the third module in a series that forms a special extended adventure (G1-G3: "Against the Giants"; D1-D2: "Descent into the Depths"; and Q1: "Queen of the Demonweb Pits"). TSR 9021

Centuries ago, a powerful wizard locked himself in his inner sanctum to dedicate his life to the pursuit of knowledge. His discoveries and magic remain sealed inside to this very day. Solve his riddle and unravel the fate of the wizard Maalzinabar and the sinister evil lurking in the depths. A 2-3 hour adventure for 5th-12th level characters

A 20-page adventure for OSE Save the wizard! A sunken cathedral on a quiet mountain lake hides a long forgotten temple to Mathanoga, God of Knowledge and wizardry. Abandoned by Man for centuries , but protected by the legend of man-eating fishmen lurking in it. Or until a few weeks ago the young wizad Elric embarked on its expedition. With help from the accademy of Greykeep he found the temple and began to explore it, hoping to uncover its ancient magical secrets. Now the wizard is missing and the accademy has put a bounty on its head: its weight in silver to whoever will find him and bring him home alive and well. Find magical secrets! Deep inside the temple are stashed many magical items, all sacred to the fishmen dwelling there, all worth dying for. Save Elric and the treasures will be yours! The Sunken Temple is an expert level Old School Essentials adventure for a party of 1-4 players. Perfect for a one shot or a random encounter in an hex crawl.

The Nexus spore is an intriguing Underdark adventure that can be sewn into any subterranean setting. This one-shot production was designed with long campaigns in mind, for when you want to break up the narrative to keep things fresh and interesting. This short adventure is ideal for players of level 5-7, although, much like the length of the adventure, it is easy to adjust. The adventure fits well into a single long session, or 2-3 short sessions. It comes complete with maps, stat blocks, boxed descriptions and a rare magic item.

The kuo-toa are a piscine race with a psychic affliction that makes them behave erratically and invent gods when feeling threatened. That same affliction gives them the power to bring those gods to life. Blibdoolpoolp is the most widely worshipped, and thus most powerful, of their gods. Blibdoolpoolp views the kuo-toa as her children despite having been born after them. Like all good mothers, she nurtures and protects. One of her chief concerns is understanding the kuo-toa’s psychic affliction, which causes them to undermine themselves whenever they strive for greatness. She discovers that a corrupted elder brain deep in the Underdark has a connection to the race; though the connection gives them psychic powers, it also turns them into powerless thralls, explaining their self destructive behaviors. Constrained by the same leash on her children, Blibdoolpoolp seeks adventurers to destroy the elder brain. Its death would free the kuo-toa, but potentially at great cost: if the kuo-toa lose their powers, will Blibdoolpoolp die?

When the PCs stumble into the Feywild, they find themselves in the middle of Mithrendain— a glorious eladrin city of grace and beauty. But as the heroes find themselves the target of mysterious attacks, they begin to discover that something rotten lurks in the city’s heart. Sunlight bathes the soaring towers of the eladrin city of Mithrendain. Gentle breezes swirl through wooded parks and along well-kept streets, and in the ancient settlement whos golden hues have seen it named the Autumn City, thousands live in peace and prosperity. For centuries, the fomorian chasms deep beneath the city have stood silent below the great magical seals that closed them in the wanting days of the eladrin empire. Over long years, the folk of Mithrendain have forgotten the dark threats of old, becoming complacent in their tranquility. And so none suspect that corruption lurks at the heart of the city, spreading out from the shadows to taint all it touches. Pgs. 104-128

This adventure is written with the intent that it takes place in the subterranean world called the Underdark in the world of Forgotten Realms, although it may be placed in other settings. Within the Underdark, Cyrog's lair can be placed anywhere though it is stated to be thousands of miles east of Gravenhollow. If you are running Out of the Abyss, you may want to have your players see the vision Cyrog Lives! Hail Orcus! (OOTA, 158). Additionally, it is recommended that this adventure be used for a party of 4 to 6 players, level 9 to 12. While merely hinted at through visions in Out of the Abyss, Orcus is roaming the Underdark unchallenged with an army of mind flayers at his disposal. Cyrog, the elder brain of a mind flayer colony in the Underdark has died. The demon lord Orcus has reanimated and taken control of it. The hive of mind flayers is now bent to Orcus's will through Cyrog as he strives to make all life in the multiverse into a vast undead horde under his control. The adventurers are contacted by a patron who gives them a special item (such as brain worms) to suppress their brain waves and make it possible to infiltrate the Cyrog's Lair without immediate detection. The adventurers must defeat or otherwise subdue mind flayers and a few guards, override the elder brain's mechanical defense system, and slay Cyrog.

Having put down a rising of giants, it was discovered that the motivating force behind their depredations was that of long-forgotten evil - the Dark Elves. Determined to seek out these creatures, a body of doughty adventurers mounted an expedition to learn the strength of the Drow and bring retribution to them (DUNGEON MODULE D1, DESCENT INTO THE DEPTHS OF THE EARTH). This module contains background information, a large-scale referee's map with a matching partial map for players, referee's notes, special exploration and encounter pieces, a large map detailing a temple complex area, encounter and map matrix keys, and an additional section pertaining to a pair of unique new creatures for use with this module and the game as a whole. A complete setting for play of ADVANCED DUNGEONS & DRAGONS is contained herein. This module can be played alone, as the second part of a series of three modules (with DESCENT INTO THE DEPTHS OF THE EARTH, D1, and VAULT OF THE DROW, D3), or as the fourth part of a continuing scenario (DUNGEON MODULES G1, G2, G3, D1, D2, D3, and Q1, QUEEN OF THE DEMONWEB PITS). TSR 9020, From 1978

Sekarvu is a typical beholder. It spent much of its youth exploring underground realms and killing everything it found. One day, it came upon a large cavern filled with violet fungi. At the edge of the cavern, it found a small band of adventurers who had all but succumbed to the toxins of the fungi's tendrils. They offered little resistance to Sekarvu as it approached and began to feed on their still-writhing bodies. With its first bite, the beholder's life changed forever. Pgs. 52-55

Agents of the fire giants of Maerimydra, a city in the Underdark, have overtaken the drow outpost of Szith Morcane. The factions seek out adventurers to free the outpost’s leaders for questioning on the giants’ activities. Can you extricate them before it’s too late?

Explore political intrigue, gene splicing, and a thrilling battle for survival in the Timescape's World Below in DOOM of the DRAGON GRAFTER, a 9th to 10th-level adventure for Draw Steel! You and everyone you know has a story of the dragon who ruined your life. You've lost so much and wondered why it had to be this way. Recently you learned that all these dragons that wreaked havoc on Orden were intentionally created to do so, all as an experiment run by a voiceless talker known as Lord Pulposa. You don't know why he did this, or how you're going to break into his lab. What you do know that you're going down into the World Below after him to make sure his schemes will never hurt anyone again. You are the Doom of the Dragon Grafter. Features: - Over 25 pages of an adventure written by the author of The Workshop Watches and The Fall of Blackbottom (that's me!) - 23 Victories worth of encounters - Lord Pulposa, a level 9 Solo Monster designed by Scott Bullock, guaranteed to terrorize your friends and enemies - Battle Maps & Positioning Maps for most combat encounters - Some Draconian fiction thrown in there for good measure - Shared under a CC-BY Sharealike so you can do whatever you want with it - A Goblin named Spanky

TENTACLES. WHY DID IT HAVE TO BE TENTACLES? A colony of deep gnomes have had their main water source taken over by a group of kuo-toa, but are the fishy folk really the ones to blame for leaving the gem-loving svirfneblin thirsty?… This adventure was originally made for a West Marches campaign, but is designed to easily fit into any standard fantasy setting. There are many areas to insert plot hooks for your own world or campaign. A 4-hour adventure for 5th-7th level characters by ALAN TUCKER

Part megadungeon, part underground expedition, Operation Unfathomable serves as both a one-shot adventure and a campaign framework. PCs are (optionally) drafted at swordpoint to recover the Nul Rod, a priceless artifact that was recently lost in a local prince's foolhardy attempt to destroy the Chaos Gods of the Underworld. The PCs have been drafted as an expendable set of pawns to venture into the vast and bewildering Underworld and retrieve the Nul Rod. With the Underworld's innumerable beasties being on high alert after the prince's expedition, the PCs must sneak through the incredibly dangerous Underworld. Fighting is not as important as stealth, fast-talking, and running away rapidly. This is the expansion from Sholtis's original Operation Unfathomable, released in Knockspell #5 (2011).

The land of Felora is a stable pedocracy off the Feso Seaway. Generally considered a safe place to live because of a low humanoid population and a large defensive wall that rings the country. The same cannot be said for the area to the west known as the Wildlands. Once a thriving human land the area was taken over in humanoid raids a century and a half ago. With the aggressions against the wall lessening the Council of Wisdom is organizing groups to go in and explore the land for possible "taming". Potential explorers will be paired off with non-combatant survey teams. Are you new adventurers ready for a job? Played at Epic Nerd Camp '17!

In this adventure, the Lord Commander of the Sharn Watch hires the heroes to investigate the murder of an actress. The investigation quickly spirals into a bloody dispute involving a dead wizard’s spell-book, political rivalries, and secrets that might foment war among the Five Nations. Pgs. 1-37

Written by the setting’s creator, incomparable RPG author Monte Cook, Ptolus: Queen of Lies is an action-packed fantasy adventure painstakingly re-designed for Ptolus: Monte Cook’s City by the Spire. Involving numerous challenging scenarios for characters of 11th level, Queen of Lies is filled with dozens of dark elf personalities, cunningly showcasing their alien culture—a world of merciless betrayal and sinister lusts. Deep below the surface, in the sunless lands of the Netherdeep, creatures of darkness build weapons and amass armies, dreaming of invasion. An attack on a peaceful elven shrine in Emerald Hill sends the heroes on a quest to retrieve stolen artifacts and kidnapped friends. All signs point to the actions of the dark elves of Ul-Drakkan, far below the city of Ptolus. However, even within that ancient fortress, there exists a deeper darkness.... Underground enemies lurk beyond every twisting passage, and strange creatures abound. The foul culture of the dark elves is both decadent and cruel, and the heroes may discover that they’ve stumbled into a web of deceit and treachery spun by the self-styled queen of the dark elves. Can the player characters complete their mission without being discovered, or will they find out, perhaps too late, that their actions been orchestrated all along by the wicked Queen of Lies? Published by Fiery Dragon Productions