The PCs have traveled to the Nine Hells to confront an outpost of devils responsible for slave raids on their homeland. In this realm of burning ash and fire-streaked skies, the infernal legions prepare constantly for war. Pgs. 138-143

As the story goes, worshipers of Bahamut and worshipers of Gruumsh spent years warring. As the dead piled up, a Bahamut faithful crafted a weapon of devastating power. Most of the inventor’s peers balked at its use, but some felt it was justified. Those few who used the weapon were twisted into mad, dark beings by its corrupting power. The rest of Bahamut’s flock locked them and the weapon away in a dungeon prison. The dungeon and its terrible secret were long forgotten—until a group of rakshasas happened across the ancient tale. Now they seek the weapon for their own designs. Pgs. 132-137

A Conspiracy of Doors is a Dungeons & Dragons adventure for five player characters of 11th level. It can serve as an introduction to Sigil, the City of Doors, as well as a group of adventurers' first taste of action at the paragon tier.

Long ago, before the arrival of civilized humanoids, a large colony of ogres thrived in the local area. When a great invasion from another dimension threatened this colony, their king, Koptila, prayed for his people to be spared. The gods heard these pleas, but commanded Koptila to sacrifice himself. The leader did so, and the clan disappeared—whisked away by the gods and lost to time. Over the years, a city grew up above the former subterranean home of the ogres, and no aspect of Koptila’s ancient bargain was preserved or remembered. Even so, the stars are aligned for the return of Koptila and his people. These powerful repatriates are unlikely to appreciate the changes in their old home. A sage has found dusty documents prophesying this return, and he asks the PCs to investigate the catacombs to defeat the potential threat to the city. The PCs travel down through city sewers and subterranean passages before finding the catacombs that the ogre colony once called home. Pgs. 48-53

The desolate, uneven country known to locals as Battlefield Downs is strewn with the scattered remains of the ancient dead. During the last terrible years of the old empire, a series of grinding military engagements played out across the rolling fields of Battlefield Downs. In one battle that was part of a wider, disastrous campaign that contributed heavily to Nerath's downfall, the Empire of Nerath's legions clashed here against ravaging gnoll packs. It is now a haunted place, where only the bravest dare to tread. Pgs. 72-79

Stonefang Pass wends its way through the mountains of the Stonemarch, home to brutal tribes of orcs. The time has come to clear the pass and gain a foothold, so that it can be used for trade between the town of Winterhaven and the lands beyond the mountains. Brave adventurers are needed to rid the pass of monsters and liberate Stonefang Keep from the orcs. Who’s up for the challenge?

Long ago, a powerful lich threatened the kingdom and was destroyed by mighty heroes. Though its phylactery could not be found, a powerful curse was laid upon the lich, trapping it inside its phylactery. This fading magic can’t hold the creature muchlonger, so the PCs must enter the phylactery itself in order to destroy the lich before it escapes back into the world. Pgs. 144-149

In the ruins of Kiris Dahn, a human town, lies a 'Slaying Stone'. The stone is said to have the power to kill any foe, though the stone is consumed in the process. The party will venture into the ruins which are the home to an assortment of goblins, hobgoblins, and kobolds. However, a mercenary band of orcs have been hired (by a benefactor who is not met in the module) to search the ruins for the Stone, and the party must find it first. The party must use caution and stealth to move through the town without alerting the denizens or the mercenaries while searching strategic points around the abandoned town to find the Stone. Eventually, the party should find the stone under the protection of an indifferent Brass Dragon.

In Treasure of Talon Pass, the player characters explore an ancient mountain garrison in search of a jade chalice reputed to be worth a small fortune. But the path to the jade chalice isn’t easy. A dragon and its kobold minions have taken up residence in the garrison, and some undead soldiers from long ago still haunt its halls as well. Nor are the PCs the only ones seeking the jade chalice. A band of orc mercenaries known as the Nightfists are after the chalice . . . and they arrived at the dungeon only minutes before the PCs

The adventurers have delved into the Abyss to strike at the Demon Lord of Undeath, Orcus. On the layer of Thanatos, the Blood Lord has many outposts from which he spreads his corruption. One of his primary lieutenants is Doresain, the Ghoul King. If the PCs kill Doresain in his lair, they will strike a real blow against the foul demon lord. Pgs. 174-179

There was no greater scholar, explorer, or collector of antiquities in the area than Hallomak Stromm. The enigmatic Stromm recently passed away, and the PCs have received personal invitations to appear at the public reading of his will. Pgs. 72-77

At Restwell Keep, you've heard that fortune and glory await those bold enough to brave the dangers of the Chaos Scar, a valley carved ages ago by a fallen star. The same tales warn that this Chaos Scar draws wickedness to it. Perhaps you can help stem this tide... and gain treasure along the way. While the location is a different keep, this adventure is an homage to B2 Keep on the Borderlands(https://adventurelookup.com/adventures/b2-keep-on-the-borderlands)

In ages past, the wizard Karavakos made a deal with devils, which resulted in him being trapped in an extradimensional pyramid, unable to escape. His only hope for escape is to lure adventurers into the Pyramid, in hopes that they will destroy his splinters and return his power to him. But his wife Vyrellis, whom he slew in a rage when the Pyramid formed, still lingers in spirit and wants nothing more than to see him laid low... Although set to allow PCs to just fight through each encounter, tips are included for PCs negotiating with the factions trapped in the pyramid.

On the outskirts of town lies an ancient temple to an unknown deity. Periodically, undead creatures issue from the catacombs beneath it. The party receives a commission from the city elders to venture into the catacombs and exterminate the undead. Pgs. 64-71

A group of snaketongue cultists has occupied an abandoned, partially sunken temple near a swamp. They grow impatient waiting for their yuan-ti master to join them, unaware that he has been slain by a rival faction of yuan-ti. Frustrated, the cult strikes against nearby villages in the hope of drawing the favor of Zehir. Investigating rumors of a serpent cult harassing a nearby town, the PCs have explored the swamp and discovered the overgrown temple. Its once-ornate stone door now hangs off its hinges, providing a narrow space for one character at a time to squeeze through. Pgs. 42-47

The hobgoblins were not the only forces that remained after Kalarel was slain. Before the Keep’s portal was fully sealed, evil spirits from the Shadowfell escaped into the Nentir Vale. They were drawn to Kalarel’s own dark soul, which remained in the mortal world thanks to a spirit-orb the priest had created to prevent him from moving on after death. The presence of these malignant spirits caught the attention of a frost witch called the Rime Mistress and her followers—unaligned territorial beasts—who rose up to defend their domain. The Rime Mistress knows that the spirits present a greater threat than the hobgoblins do, so she and Prang, the Iron Gauntlet leader, have agreed to an uneasy truce. Thus, the hobgoblins and the creatures of the Cairngorm Peaks are united in their struggle against Kalarel’s spirit army.

This is Part 1 of an adventure designed for characters of the 20th to 21st level About 200 years ago a horrific massacre took place on the remote Soron island of Heikun. For months, the deranged and corrupt priests had sought to create a race of hybrid Snake-Men...a race which they believed once existed in Soro. They kidnapped folk from surrounding villages and took them back to their temple. There they performed unspeakable rites and experiments. Sensing their debasement, the dark spirits of the mountains called to the priests in their dreams, luring them down into the vast sub-levels beneath the Pyramid. Somewhere in the cavernous depths they were touched by an eternal evil and given horrific new forms. The deformed priest-things of Heikun crawled back to the surface, systematically destroying all living creatures in their path, including the city's hapless, ineffective leader: the inbred boy-king Yusef.

In the aftermath of AD&D Second Edition's "Return to the Tomb of Horrors," the demilich Acererak was thought destroyed. In truth, his spirit lingered and now after eons he schemes once more to achieve divinity. The characters must travel to three extraplanar dungeons, in addition to the remains of the original Tomb, in order to stop this from coming to pass.

A vast Feywild swamp slowly seethes into the mortal world, conjured by a malevolent hag. The Murkendraw's unstoppable progress widens Rotten Ethel's dominion by a few steps each day, and with it, the hag's ambition. When Rotten Ethel kidnaps the fairest pixie of all, the swamp's advance suddenly quickens. The fairy folk need brave heroes to turn back the tide and venture forth to rescue Glitterdust.

Something stirs in the dark heart of the Warwood, and in response something stirs in the stars. A simple encounter with bandits on the road leads the PCs to a frightening place where even dreams are deadly. Cultists seek to free the soul of a terrible entity from beyond the stars. The PCs must retrieve the soul vessel of a long-dead evil paladin to stop cultists’ plan from coming to fruition. Pgs. 60-92