In the city of Waterdeep rests a tavern called the Yawning Portal, named after the gaping pit in its common room. At the bottom of this crumbling shaft is a labyrinthine dungeon shunned by all but the most daring adventurers. Known as Undermountain, this dungeon is the domain of the mad wizard Halaster Blackcloak. Long has the Mad Mage dwelt in these forlorn depths, seeding his lair with monsters, traps, and mysteries—to what end is a constant source of speculation and concern. This adventure picks up where Waterdeep: Dragon Heist leaves off, taking characters of 5th level or higher all the way to 20th level should they explore the entirety of Halaster’s home. Twenty-three levels of Undermountain are detailed herein, along with the subterranean refuge of Skullport. Treasures and secrets abound, but tread with care!

Of all the inhospitable domains in the RAVENLOFT@ campaign world, Bluetspur is the cruelest and most gruesome. Nothing grows in the endless night, and lightning periodically falls like rain. The only place to escape those storms is inside the mind flayers' complex under Mt. Makab, but that is the last place where any sane person would want to go. The High Master Illithid has been hatching black plots by hatching vampiric mind flayers in his laboratories! His prodigies are horribly insane, but if he can complete his plans, he will achieve a new level of dark immortality. A pair of heroes has stolen the key to his success, but they have paid a heavy price for their bravery and are in desperate need of aid unlooked for. Meanwhile, the Lord of the Realm watches over the proceedings and plays havoc with the wits of both sides, sapping strength and will with all-powerful thoughts of darkness. A party of adventurers will need all of their skills to escape this black domain without the loss of life, power, or sanity! Enter now the perpetual twilight realm of Bluetspur, home to mind flayers, a land of relentless nightmares. There's no rest for the wicked or the good in this domain. Once caught within the borders of this desolate land, the characters must complete their mission without delay or lose their minds and become slaves of the Lord of Bluetspur. TSR 9264, from 1992

The PCs are singled out by happenstance as prophesied heroes who will find and return a great wizard to his family. Once brought back to the the family chateau, they are brought on as paid companions and free to explore the location as they wish. This is a large sandbox style adventure with several plots going on, including assassination, a wedding, false accusations of murder, and many machinations of the nobles to solidify or gain power. Whole this is going on the PCs are dropped into dream sequences where they learn more about the missing wizard and learn how and where to find and free him

4e's 'Expedition to the Barrier Peaks'... on the moon! Using the technology of a lost civilisation, illithids have been cloning influential people. The PCs must navigate a strange sci-fi environment and defeat the illithids. Additional items & malfunction rules can be found in Dragon #410 & Gamma World 7e.

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

An escaped duergar slave stumbles into the village of Elventree. With her she brings a malady that grips the small settlement in a bout of madness that seems unshakable. Can you find the source of the madness and save yourself and the village’s inhabitants? A four-hour adventure for 5th-10th level characters.

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.

Avalanches are hardly news in Icewind Dale. The frequency to which it is occurring, however, defies logic. What is the cause of this strange phenomenon? What horrors could have unleashed such force of nature with such reckless abandon? Horror Beneath the Frost is a slasher horror adventure set in Icewind Dale, deep within the Reghed Glacier. It features yetis, mind flayers and a boneclaw! The adventure is designed to be easily dropped into: • Any homebrew campaign where avalanches occur. • Icewind Dale: Rime of the Frostmaiden campaign. • Plague of Ancients Seasonal Campaign for the Adventurers League (AL) organized play program. Inside you will find: • A slasher horror adventure optimized for five characters with an average party level (APL) of 8. • Scaling advice for three to seven 5th to 10th level characters. • A printer-friendly version of the adventure. • 4 digital maps importable to Roll20, Foundry VTT and your VTT of choice. Includes gridded, grid-less and printer friendly versions of the maps. • D&D Adventurers League compatible adventure (Dungeon Seed: This Seems Familiar | DC-POA-JL01)

You stand before the Sha’sal Khou elders as the most diverse gith hunting party ever assembled. Are you powerful enough to keep the mind flayers from enslaving your people once again? You’ll have to race across the planes to find out. A six to eight‐hour adventure for six players.

a baron recruits the party to find a set of magical swords as well as explore a mine shaft that connects to the under dark

A missing mage... A ruthless band of kidnappers... A sinister conspiracy... Night Below, the first epic campaign adventure for the AD&D game, is designed to take the player characters from 1st level to 10th level and beyond. The PCs start as beginning adventures on a routine courier mission who soon become drawn into combating a sinister plot that menaces the pleasant land of Haranshire.

A prescription for evil. The king's question is, "Do you make house calls?" To Cure a Kingdom is an adventure for ADnD, set in and around a small city state that is suffering from a deadly disease of magical origin. The party must set out into the swamps in search of a cure. Features monsters with psychic powers as well as extra-dimensional travel. Adventure may be connected to further Underdark adventures with relative ease. Pgs. 8-25

The players get more than they bargain for when answering a night-time call for assistance from a mutual friend. Can they escape the githyanki prison known as the Crucible and find their way home from the Astral Plane? Designed for characters of 5th to 9th level, the Crucible can be played as a standalone one shot adventure, or as the first in a four part series of connected one shots that see the party fight their way to hell and back.

The Free City: a shining gem in the crown of cultured civilization. Beneath the surface of this bustling metropolis is a rot, festering in the darkness, manipulating the lives of those unaware of its presence. Now a small adventuring band from out of town may be in over their heads. Their actions in Diamond Lake have attracted the wrath of one of the city’s hidden masters. A gang of infiltrators and an enigmatic mastermind plot their destruction, and only tracing the rot to the root can stop the onslaught. "The Hall of Harsh Reflections" is the fourth installment of the Age of Worms Adventure Path, a complete campaign consisting of 12 adventures, several "Backdrop" articles to help Dungeon masters run the series, and a handful of poster maps of key locations. For additional aid in running this campaign, check out Dragon's monthly "Worm Food" articles, a series that provides additional materials to help players survive this campaign. Check out issue #336 of Dragon for five attractions to tempt your PCs to spend some of their hard-earned loot. This issue of Dragon also features an Ecology of the Spawn of Kyuss, one of the central creatures featured in this campaign. Pgs. 34-60

The Fortress of the Yuan-Ti describes a fortress build into a cliff side and the slave village outside. The Adventure is the third of three but can easily be played by its self. The adventure revolves around the players discovering the dark plot to revive the demon Sertrous and then stopping it. The adventure describes the outside, inside, and hanging towers of the fortress. The adventure concludes in a forth extra-planer tower were you fight the boss. It also includes 4 sidetracks from portals that explain how they get the materials for the ritual. Final part of the Barrow of the Forgotten King series.

When Volothamp Geddarm hires you to recover a missing key, you find yourself wrapped up in a series of murders in Lower Skullport. Can you find the killer before they find you? Part One of the Skullport Shakedown trilogy. A Two- to Four-Hour Adventure for Tier 2 Characters. Optimized For: APL 8

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?

Ranked in 2004 as the single greatest adventure of all time by Dungeon magazine, this is a compilation of three series of modules: the G series "G1-2-3 Against the Giants" (G1 Steading of the Hill Giant Chief, G2 Glacial Rift of the Frost Giant Jarl, G3 Hall of the Fire Giant King), the D series (D1 Descent into the Depths of the Earth, D2 Shrine of the Kuo-Toa, D3 Vault of the Drow), and Q1 Queen of the Demonweb Pits. The characters begin by attempting to stop giant raids that have become prolific. They find out that the giant alliance is caused by the drow. They then descend into the Underdark in order to find the drow and stop their sinister plan. TSR 9179

Side-Trek adventure When your PCs gain access to the teleport spell, their whole world changes. That simple spell opens up instantaneous, long-distance travel. No more long overland journeys or dangerous retreats through hostile territory. All it takes is clasped hands and a word from the wizard, and poof! The PCs are where they want to go. Except that it isn’t that simple, because teleport isn’t foolproof. The off-target teleports are a matter of scattering your PCs someplace else on the map and forcing them to get their bearings and make the long overland journey anyway. But this Side Trek focuses on the really intriguing column on the teleport chart: “similar area.”

Encounters in the Savage Underdark is a 150-page supplement containing mini-adventures, NPCs, locations, and magic items,from eighteen of the DMsGuild's best authors.This incredible 150 page supplement features 24 amazing new Underdark adventures. Visit Annarei's Garden Encounter an insane aboleth Interact with traveling merchants Attend the Fire Fest Perform an Underdark heist and so much more....