In the fourth installment of the Into the Underdark adventure series, characters come face to face with the heretofor unseen puppet master behind most of the strife and chaos in the Shadowed Hallows, Gyldrith the Chosen, a dreaded deep dragon! Includes: Three all new maps of Gyldrith's lair, and those of her minions Two all new monsters, the Ancient Deep Dragon and her Warlock of the Deep Dragon A new player option, the Deep Dragon patron for the Warlock Class. Unnumbered maps suitable for use in your favorite VTT Continues the story from Into the Underdark Part 1 - The Descent with areas and NPCs from The Shadowed Hollows Gazetteer

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.

This is a trapped corridor which can be dropped into any castle, dungeon, ruin or underground adventure. It features full rules on how to scare the living be-jesus out of your adventurers and have sone great fun with them too. Get ready... as the 'Umber Eyes' is ready to receive you...

The most deadly dungeon ever devised! High-level characters brave the unexplored corridors of Deepearth to confront perhaps the most feared adversary in the AD&D game. The second chapter of the Bloodstone Pass saga follows the conclusion of the desperate war against the bandit army. A cold and bitter winter drives the villagers to the edge of starvation, and numerous horrors strike the town of Bloodstone Pass. Join the adventure as the heroes explore the depths of the ancient bloostone mines, now inhabited by fearsome demons. There they hope to uncover the fantastic treasures rumored to exist in the unknown darkness. But deep within the mines, all is not what it seems.... This module uses the new rules from the Dungeoneer's Survival Guide and Wilderness Survival Guide. The adventure also includes optional BATTLESYSTEM scenarios fought entirely underground. These supplementary products are not required to play the adventure, however. TSR 9168

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

What elder evils lurk in the depths of the freezing mountain ruins? Find out in The Stoneheart Ruin! The adventure features: An adventure set in a desolate, wintry mountain landscape. 16 pages full of intrigue and mystery, containing full color maps, plus 2 unique monster stat blocks. Provides a great introduction to Mind Flayer lore and mythos for Tier 1 players. Can easily be set in the Spine of the World for use in Rime of the Frostmaiden. Let your characters test their mettle as they climb and face the ancient dangers lurking in the cracks of The Stoneheart Ruin! “I have no explanation for any of these finds. We heard disturbing noises coming from further within the mountain; thunderous and growling.” Excerpt from a pamphlet, signed: “Koralia Meadring, Anthropologist Extraordinaire” Koralia needs you to investigate her most recent discovery: a ruined cavern deep in the mountains. Her small team of academics did a cursory walk-through and think they've found a big breakthrough! However, they left in a hurry after being frightened by the horrors they heard coming from deeper in the mountain. They escaped and found one of their team was missing - a goliath named Marek. You must climb the mountains and locate the ruin, make certain that it is safe for study by Koralia’s team, and if possible, find and rescue Marek, whose fate is uncertain. Made during the November 2020 RPG Writer's Workshop.

Ruins of the Grendleroot is a book of ten easy-to-prep and easy-to-run adventures for the fifth edition of the world's most popular fantasy roleplaying game. Designed for characters of 1st to 5th level, these adventures take place in the caverns, chambers, tunnels, and ruins of Blackclaw Mountain, within which lurks a strange otherworldly sentience known as the Grendleroot. Ruins of the Grendleroot focuses on the sense of mystery and wonder that comes from exploring ancient ruins and lost chambers. The central hub of these adventures, Deepdelver's Enclave, is a frontier outpost overlooking the ruined city of Shadowreach, set deep within the mountain. In Deepdelver's Enclave, adventurers and explorers recount tales of their explorations, trade treasure and artifacts, and enjoy their shared love of uncovering the mysteries of the mountain.

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

The Red Plumes have increased patrols in the region surrounding Hillsfar, and a string of disappearances has followed in their wake. Naturally, this has roused the suspicion of the factions. Join your factions and find out the truth behind the missing farmers. A four-hour adventure for 1st-4th level characters.

The Zhentarim ask the party to investigate what happened in one their most important underdark outposts. If the party accepts, they'll have to deal with maddening darkness, grimlocks, an insane kenku assassin and unpredictable mixtures of potions. A short, fun dungeon romp that is easily adapted to other settings and other patrons. The combination of utter darkness and a villain based on sound makes for fun shenanigans on the side of the DM. Feasible as a one shot for an efficient party. Two tendays ago, Zhentarim agents were to transport a shipment of rare potions between their Underdark outpost and the surface world. The shipment has yet to arrive, and the outpost is not responding to any sending spells. Growing worried, the outpost’s overseer sends a group of hireswords to investigate and return it to Zhentarim hands. This particular adventure deals with the delusions of madness of Fraz Urb'luu. It also features Muurmic, the mad kenku first described in the December 2015 issue of Dragon+.

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

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).

Are your player's moving out of Velkenvelve? Enjoying a stroll along the shores of the Darklake? On a day trip from Gracklstugh to Neverlight Grove? Sightseeing near Blingdenstone? Then Journey Through the Center of the Underdark is for you. Journey Through the Center of the Underdark contains several detailed encounters ideal for fleshing out traveling days between locations in Out of the Abyss. Furthermore, these encounters could be readily inserted into any 5th Edition Dungeons & Dragons Underdark oriented Forgotten Realms or home campaign setting. Designed for a party of 4-6 fourth through sixth level characters, with easy notes for adjusting encounter difficulties for lower or higher level groups, Journey Through the Center of the Underdark should provide 8-10 hours of exciting in game adventure. Written for your Rage of Demons Out of the Abyss campaign, Journey Through the Center of the Underdark is ideal for any descent into the depths your characters might take. Enjoy!

After a drow girl goes missing, characters must delve into the depths of the Underdark to bring her back. As they journey through the dark, characters discover not all monsters are monstrous and webs are capable of restraining all manner of creatures; in fact, they can capture magic itself.

On a nameless, featureless demi-plane the Tarrasque rages across an all-encompassing nothingness. Last seen on Faerun a century ago during the cataclysm of Odobaz, the battle mage order of the Eldritch Storm sacrificed itself to banish the mighty titan to its demi-plane prison. Now a foul power emerges in the High Ice and nightmare visions of the Tarrasque trampling cities wrack the minds of the living—can your adventurers defeat the Horror Under the Mountain?

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

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?

"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.

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 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.