In the Anauroch desert, darkness is growing. The followers of the Vile Spore Goddess Zuggtmoy have stolen the dreams of the Bedine Seeress Deja, trapping them in an eldritch artifact. Unless her dreams are returned, the Seeress will descend into madness, and her people along with her.

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.

The Underdark is a subterranean wonderland, a vast and twisted labyrinth where fear reigns. It is the home of horrific monsters that have never seen the light of day. It is here that the dark elf Gromph Baenre, Archmage of Menzoberranzan, casts a foul spell meant to ignite a magical energy that suffuses the Underdark and tears open portals to the demonic Abyss. What steps through surprises even him, and from that moment on, the insanity that pervades the Underdark escalates and threatens to shake the Forgotten Realms to its foundations. Stop the madness before it consumes you! Note for DMs: This adventure is not for the faint of hearted, to run or to play. The module starts with 10 NPCs traveling with the party through the grueling Underdark. This number can grow. The encounters within the book are often incredibly deadly for the characters that would be going through it. This is because the module expects them to run or talk their way through the events, or, in some cases, the module expects them to lose. If your players aren't the kind of party to run, talk, or surrender, do not get this adventure. The module almost requires that you use milestone leveling because the experience provided does not commonly get players to the levels they should be once they get to certain milestones in the story (7th when they leave the underdark, 15th when they face the demon lords.) Good luck and happy questing.

Dark Water Trap is a mini-adventure that has a single encounter that involves Duergar using darkness and anti-darkvision to get the player to fall into a Pit trap full of water, so that the party will drown. The encounter either works as a standalone (Ie. the Duergar have been causing trouble), or as a part of a larger adventure or dungeon, Duegar or otherwise. Pgs. 26-27

Expand your game with this collection of 56 NPCs of various Challenge Ratings, thirteen of which include maps and details of their lairs. Add these NPCs as a side-quest, a main villain, a one-shot, a bounty for easy money, or however else you wish. Written by some of the best-selling authors on the Dungeon Masters Guild and outstanding podcasters, each NPC includes an image, a backstory, motives, flaws, and a stat block. Some even include new magic items!

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

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

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

Zhentish soldiers, Maerimydran drow, and Sharran cultists have forged a dark alliance to subjugate the peaceful land of Shadowdale. Elminster's tower lies in ruins, Lord Amcathra governs at the sufferance of the dale's conquerors, and the very Weave of magic in this embattled land seems to fray with each passing day. The Zhentish yoke lies heavy over Shadowdale—but the Dalesfolk are ready to fight for their freedom, if only they can find true heroes to lead the way!

A mind flayer has called for a massive conference of monsters in the Underdark beneath Hillsfar. Trolls, umber hulks, demons, and more have answered the illithid's call. To infiltrate this gruesome menagerie, you must embrace the monster within yourself.

An unexpected envoy arrives in Sporedome and offers to give aid against the fire giants of Maerimydra, if you are willing to help his people with a small problem. A two-hour adventure for 5th through 10th level characters. Optimized for five 8th level characters.

"The module takes place in a large cavern that is part of an extensive underground cave network. It can be used as a side-trek encounter in the Undermountain or Night Below campaign." -- from the adventure. Includes a small keyed map of the cavern.

More than a hundred years ago, Delbera Axebringer—a mighty warrior and dwarven leader—slew the necromancer Audalot Karexin, but spared his young apprentice Zohir. In the ensuing decades, the bitter survivor brooded and plotted her revenge. Now, descendants of the Axebringer clan are vanishing, dragged screaming into the darkness by the animated bodies of their fallen kin. The Axebringers and their hometown of Davarn need heroes to break this family curse. What mysteries lie sealed within Delbera Axebringer’s ancient abandoned fortress? And what challenges lurk along the Blighted Path winding through the Darklands beneath Golarion’s surface? Down the Blighted Path is a deluxe adventure for 5th-level characters, and includes 64 action-packed pages of exciting battles, supernatural mysteries, and monstrous foes, plus a gorgeous double-sided poster map featuring an overview of the dwarven trading post of Davarn and a miniatures-scale battlemap! The author of this adventure, Monica Marlowe, was the winner of the 2015 RPG Superstar contest, in which hundreds of unpublished authors competed or the chance to write a Pathfinder Module. In addition to her adventure, this book contains a host of new monsters and magic items designed by the contest’s runners-up. Players can expect to reach 7th level upon completion of this adventure—if they can survive its deadly haunts, Darklands horrors, and furious villains both living and undead!

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 greatness of a dwarven citadel is measured by its greatness of wealth. The dwarves steadily work mines and forges to fuel the wealth needed to make their presence known throughout the realms. Unfortunately, this also makes them known to those that would seek the opportunity to steal their glory and riches. This story occurs in a place that has experienced this struggle for millennia. New threats emerge as old threats become rivals through the tides of time. This story... your story... is another chapter of this ancient struggle.

"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.

A strange journey through a living cavern. A request for help to rescue a mining crew leads a group of adventurers into a cave that has seemingly come to life, gripped by a melancholy wave of sadness and memory. In dark caverns where mushrooms walk, vines dance, walls watch, and stones speak, will your band of adventurers become heroes? Or will they be lost within the Mines of Memory? Mines of Memory is a short, 2-3 hour adventure for characters of levels 1-3. It is a delve into a cavern system that has become a Psychic Resonance environment, awakening the caves themselves. PCs will enter to rescue the miners, find the source of the mine’s awakening, and bring peace to a noble creature trapped in its own nightmare.

Tieflings are raiding a dwarven expedition under a shield of magical darkness, but if the PCs can supply the dwarves with giant scarab beetles capable of generating potent bursts of magical light, they might just survive. Unfortunately, they'll need to escort the herd of giant beetles through the Underdark first. A D&D adventure for 3rd-level characters.

The final confrontation with the giant, King Snurre, and the entry of mighty adventurers into the caverns under his stronghold (DUNGEON MODULE G3, HALL OF THE FIRE GIANT KING) discovered the Dark Elves, the Drow, had instigated the giant alliance and its warfare upon mankind and its allied races. 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 cavern area, encounter and map matrix keys, and an additional section pertaining to a unique new creature 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 first part of a series of three modules (with SHRINE OF THE KUO-TOA, D2, and VAULT OF THE DROW, D3), or as the fourth part of a continuing series of modules which form a special progressive campaign scenario (DUNGEON MODULES G1, G2, G3, D1, D2, D3, and Q1, (QUEEN OF THE DEMONWEB PITS). TSR 9019

Tonight, a ceremony of light is taking place on the surface. Meanwhile, a world away in the city of spiders, a drow matron solidifies a pact with soul-consuming entities who require great sacrifices in trade for unimaginable power. Drow eyes turn to the surface. This book contains a mega-adventure and setting, taking characters across the surface and into the depths of the world. Adventurers will meet unique denizens, battle horrors of the Underworld, explore epic locations, and fight to stop the rise of the drow.