The Underdark holds many secrets. A series of earthquakes and eruptions have rocked a normally placid land. Strange creatures sighted in the dark of night raise fears across the already disturbed countryside. As tales of a lost race that once warred with the drow begin to surface, only the boldest adventurers dare to descend into the shadowy darkness.

From the backcover: "Once a generation, they say, a strange comet appears in the sky overhead and the gates of Firestorm peak swing open, (twenty-seven years ago, your father led his band of adventurers into the mysterious mountain, never to return. Now the Dragon's Tear once more flickers in the sky, and the glass gates on the mountainside beckon. Will you pass through to discover the secrets that await beyond the portal none has ever dared and returned? The Gates of Firestorm Peak is the first adventure designed especially for use with the new rules presented in the three PLAYER'S OPTION books: Combat & Tactics, Skills & Powers, and Spells & Magic. While it can also be played using just the AD&D® game core rules (the Player's Handbook and the DUNGEON MASTER® Guide), this adventure offers a perfect opportunity to experience all the potential of the new optional rules. One of the highlights of this package is the first PLAYER'S OPTION player character record sheet. To meet the challenges of Firestorm Peak and escape with their lives, heroic adventurers must battle dark dwarves in their underground city, explore the abandoned caverns of the Elder Elves, and deal with weird alien entities from Beyond. Their goal is to stop the Master of the Twisted Caverns and his dark minions from completing his sinister plot before it's too late . . . if they can. Included in this product are a 96-page adventure book detailing the dungeon that lies beneath Firestorm Peak, 4 full-color poster maps detailing all the important locations in the complex, and a sheet of 56 counters for use with the tactical maps in major combats."

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.

While in the peculiar village of Basht, a town full of strange customs and superstitions, an elderly woman asks you to check in on her grandson, a Gondite tinkerer testing out his latest invention in a nearby cavern. Sounds easy enough, right? A Two-Four Hour Adventure for 5th-10th Level Characters This adventure originally debuted as custom content for the 2019 U-Con convention in Ann Arbor, Michigan. Visit them at https://www.ucon-gaming.org/

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).

Under the Flooded Forest grows a toxic maze of magical fungi called the Nidus. From this horrid realm a cult has struck a terrible blow against the wood elves struggling to regrow the trees in the forsaken swamp of the Flooded Forest. The elves, on the brink of extinction, need the adventurers to navigate this deadly labyrinth and recover a precious object. But the tunnels here crawl with spore-laden beasts and demons, and the very air itself is poisonous.

From the magazine: "The monster you're sent out after is so dangerous that even mind flayers fear it. And the illithids want your help!" Earthquakes hit the area around Needlespire mountain, affecting both dwarven and deep gnome villages, and the local mining industry. Deep gnome expeditions discover an illithid outpost! This adventure includes roleplaying encounters with both deep gnomes and illithid in their quest for the true cause of the earthquakes. The creature causing the earthquakes is a draknor which has sent its huge tentacles into the earth seeking magma to fuel its growth. Pgs. 38-60

The Shattered Circle is an AD&D® adventure for four to six player characters of 1st to 3rd level. For many ages, the standing stones known as the Circle of Cahervaniel have stood on a grassy hilltop, unremarkable and unmenacing, but something has changed. A powerful artifact deep within the earth has been uncovered, and its evil power has corrupted the recent inhabitants of a dungeon complex. The chitine live within, a cross between humans and spiders created by the drow, but trying to live a quiet existence. The evil Foundingstone has corrupted some of the chitine, and split their society in two, bringing them to conflict. Adventurers who navigate the chitine factions and dangerous dungeon will need to end the threat of the Foundingstone and the solve the mystery of the strange dark unicorn Mizar that has appeared recently around the stones. Interestingly, one of the unique magic items in this adventure, Icerazor - is said to have grown from a shard of Frostrazor, a sword that appears in a famous later adventure - Return to White Plume Mountain. There is a brief mention of Suloise, so it can be considered a Greyhawk adventure, but clearly states it can be placed anywhere.

If absolute power corrupts absolutely, Matron Maelora best beware; her plans for total domination of the Underworld are already close to satisfactory completion, while attacks on the Upperworld have become increasingly successful. The other power-hungry drow families of Holoth may despise her but they know a true leader when they see one, and House Gullion has been revealed as the family to lead them all on the path to glory. With the entire Underworld in chaos and the Spider Goddess regularly communing with her chosen Matron, far greater dreams than mere regional conquest are within the grasp of the drow, as Maelora prepares her grand dark elf army for victory! With other mystical allies standing firm with the Matron, other Underworld races beneath her heel or cowering behind fortified walls, and every drow ready to play their part when she gives the word, what could possibly stop her from achieving her final triumph and fulfilling her destiny? But even the greatest of plans has a flaw if you look hard enough, and a party of stout heart and strong resolve can make a difference. At first, such a party may well believe it is on a smaller adventure, perhaps to win a few baubles or some small acclaim by rescuing a few kidnapped villagers. Soon, however, those adventurers will realise that much more is at stake, and that they are the ones who will need to make moves against the evil Matron Maelora and her increasing dominance if both the entire Underworld and Upperworld are to be saved. But how will they go about it? Can they ensure their own success when an entire city is standing against them? Only they have the chance to halt the Rise of the Drow! Published by AAW Games.

Hunt for a Legendary Treasure! Deep beneath a peaceful valley lies the vault of the legendary drow adventurer Larin Karr. Rumor has it Larin Karr has gone, but his vast treasure acquired from years of plundering hordes in the Underdark still remains. Can you find and loot the impenetrable vault? The Vault of Larin Karr details Quail Valley, its residents and monsters, and the twisting tunnels of the Underdark that stretch beneath it. The Vault of Larin Karr takes PCs from 4th to 9th level, during which time they fight dragons, find a missing statue for a band of renegade elves, save the village of Pembrose from scheming hobgoblins, and explore the Underdark and its many dungeons - including the legendary Vault itself! Contains new monsters and magic items! 2003 ENnie Award Silver Winner: Best Adventure

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.

Originally designed as a convention module, this adventure sends the heroes into the underdark to do battle against the mysterious denizens of the deep! A drow housemistress commissions the characters to acquire a mysterious weapon known to be in the hands of her dark elf enemies. Locating, identifying, and acquiring the magical weapon leads the heroes on a great trek across the underdeep, where they must battle svirfneblin, a powerful lich, and enemy drow. This adventure us specifically designed for play by drow characters, but can be used with any adventuring party. Pregenerated drow characters are included.

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

Part 3 of the Shackled City Adventure Path "Wherein a tribe of the Sea Mother's children suffer for sparing the life of a mad prisoner they probably should have eaten." Synopsis: The adventure begins with an Umber Hulk attack in the middle of the city. The fame gained by assisting during the attack allows them to gain the notice of a representative of Davked Splintershield. The group is asked to rescue Zenith Splintershield from a Kuo-Toan temple in the Underdark. But to find it, they have to visit Crazy Jared to locate an entrance to it. Upon journeying to Crazy Jared's, they fight Hookface's offspring. After more travelling, they are able to descend into the Underdark. Once they find the Kuo-Toan temple, they must fight through many hard challenges, only to realize that Zenith is not a prisoner, but instead is a prophet. Zenith does not go willingly, and so must be captured. Pgs. 28-61

The Ghost Tribe of Orcs were driven from their home under Wyvern Tor by some terrible evil. They marched to Phandalin and attacked only to be defeated. Then, the heroes journeyed to the orc’s former settlement beneath Wyvern Tor and found the source of the orc’s sardonyx and the umber hulk that drove the orcs out. Now, the party has to go deeper to deal with the terror from the Underdark that caused all of this excitement.

Gyldrith the Great is coming, and she is not happy. How long have you been down in these caves? Days? Weeks? More? Time is hard to track this far underground. And so much has happened since you descended into the tunnels beneath Dhonin’s Lookout. Now, you stand guard at the Great Gate of Naakrasad. Exhausted from your past battles, and your narrow escape from the cat and mouse games of the ancient deep dragon, Gyldrith. You can hear the hoots and hollers of her horde of bloodthirsty minions just beyond the city walls. A battle is coming, a battle against great odds. A battle that will test your mettle like none before. And you wonder if you are up to the task. A massive battle ranging across the small city of Naakrasad in the Underdark. Giant map of the city of Naakrasad with close-up details of the major battle sites in the adventure. Several new monsters, including the vicious Half-Ogre Hound Master and his deadly Hell Hound pets. Unnumbered maps, including the entire city of Naakrasad, to use in your favorite VTT.

In Prisoners of the Drow, a band of adventurers storm a drow outpost, confront the drow mage in charge of it, and rescue prisoners held within. The heroes must bypass traps and devious defenses to reach their goal and accomplish their mission. The adventure is designed for a party of five adventurers between levels nine and twelve. It features: Encounters by Level - Varying types and quantities of creatures are suggested based on the party's actual level, allowing each encounter to present the appropriate challenge to the party. Encounter Notes - Suggestions for how to run combats are provided for game masters who place an emphasis on engaging, tactical battles. Inciting Action - Suggestions for ways to present the adventure to players are provided. Ease of Use - The format and style of the document allows the game master to find information quickly while running the game at the table. Detailed Maps - What's an adventure without maps? Not much else to say here. This adventure is designed as the first in a two-part series. The second adventure Into the City of Spiders takes the adventurers into a drow compound far from the surface. https://www.drivethrurpg.com/product/247674/Into-the-City-of-Spiders

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.

For the most part, the town of Ockney’s Hold has always been a peaceful place—bordering on boring. The most interesting things going on in this frontier mining settlement include the annual livestock fair, the cost of spirits at its various inns, and speculation fueled by those same spirits as to what foul things are being dumped into the river by the ore refinery. Recently, however, the usually placid Baron Reinson has begun to act erratically, ignoring most of his counselors, giving more responsibility to his equally erratic chamberlain, and replacing key figures in Ockney’s Hold with outsiders. With no clear answers as to what might be behind the baron’s strange behavior, his last loyal counselor seeks out a band of adventurers to help. Will these brave heroes be able to get to the bottom of a widening conspiracy? And can they expose the terrible and unseen forces manipulating the baron in time to save Ockney’s Hold? Published by Gamehole Publishing.

Troubles simply mushroom in the Underdark. The alchemist would like some fungus and spores, but no one wants to get them. Perhaps you could help. The adventure begins with the party finding a caravan. In addition to being able to trade with these NPCs, the party also can be hired by an alchemist to bring bag some red fungus and some Myconid spores from underground. Underground, the party will have a chance to interact with friendly Myconids and venture through a large labyrinth of passages (this labyrinth isn't mapped and is dealt with through storytelling, random encounters, and roleplay). The adventure culminates in a battle between the Myconids and Flinds, and the players can participate. Pgs. 4-12