Dangerous Designs

A war criminal is broken out of prison by well-armed kobolds working for a mysterious mastermind who threatens the gnomish city of Hupperdook. “Dangerous Designs” is an adventure that takes characters from 1st to 3rd level, and which introduces them to the Western Wynandir region of the continent under the rule of the Dwendalian Empire. This region is geared toward adventures that involve monster hunting, political intrigue, and the war with Xhorhas.

If your players are using the heroic chronicle to create their characters (see chapter 4), they might wish to create characters who grew up in the Zemni Fields or Marrow Valley, giving them a closer connection to this region and to the Dwendalian Empire. For characters not from Western Wynandir, the players should consider what has drawn those characters to Hupperdook. Because this adventure ties directly to the Kryn Dynasty’s conflict with the Dwendalian Empire, you can also ask each player to consider their character’s stance on the war and how the war might tie into their background.

Story Overview

The characters are drawn into this adventure in the lower regions of the city of Hupperdook, an industrious gnomish enclave where long days of hard work in the forges and scrapyards end with evenings of extensive celebration and debauchery. A brilliant human engineer named Huron Stahlmast was assigned to Hupperdook by the Dwendalian Empire, where he led the development of weapons for the war against the Kryn Dynasty. After years of rising disapproval of his ideas and methods, Stahlmast was ousted by the folk of the city due to his eccentric experimentation and brutal means of testing his weapon designs. Shamed and without funds, the inventor allowed his dark hatred to push him to meet with agents of the Kryn Dynasty, seeking aid that would let him complete his work and enact his revenge.

With the Kryn resources now funneled to him, Stahlmast has amassed and trained a force of kobold minions to help him steal resources from Hupperdook and establish a secret subterranean base deep within the Silberquel Ridge. As construction of his experimental weapons nears completion, Stahlmast plans to use those weapons against the empire that cast him aside.

Stahlmast’s plot to take over Hupperdook and hobble the military might of the Dwendalian Empire’s gnomish war machine begins with a prison break. The target is a Kryn operative whose assistance Stahlmast needs. From there, the characters are drawn into the growing chaos orchestrated by Stahlmast and his minions, chasing down leads and eventually confronting the mad inventor within his mountain lair.

Adventure Summary

In the first part of the adventure, even as the characters arrive in Hupperdook, a jailbreak sees a dangerous goliath prisoner of war named Sken Zabriss freed by a group of cloaked kobolds. Their violent escape route crosses the characters' path before they flee into the night. The city’s watchmaster, Bram Gulchswattle, hires the characters to investigate the breakout and to discover the whereabouts of Zabriss and her kobold allies.

Clues lead the adventurers to a waterfall-cloaked cavern that conceals Sken Zabriss, a force of kobolds, and a master artisan missing from the city. When the characters complete this encounter, they reach 2nd level and can return the subdued Sken Zabriss to Hupperdook and collect their reward.

In the final part of the adventure, the characters are urged to continue their investigation by entering Stahlmast’s base—or they might pursue Sken to that base if they allowed the goliath to escape. Once inside the halls of Stahlmast’s mountain compound, the adventurers must uncover the depths of the mad inventor’s betrayal of the empire. The dangerous incursion culminates with an all-out battle against Stahlmast and his prototype war machine.

Setup and Starting Points

Before the adventure begins, talk to your players about why their characters might have made the journey to Hupperdook. You can provide details regarding the city and the surrounding region as outlined in chapter 3. You can also ask the players if they want to share any of their characters' goals, which might provide reasons for their group to come together. Seeking paying work, purchasing equipment, and wanting to join the war effort are all common reasons for traveling to the gnomish enclave.

Use this time to also discuss if the characters are meeting for the first time or if any of them already know each other.

A Boom in the Night

The adventure begins with the characters arriving (whether singly or together) in Hupperdook. Map 5.4 shows Lower Hupperdook and marks the locations of the Ironlot and Assembly Yard sections of the city.

Once the players are ready to begin, read or paraphrase the following boxed text to set the scene:

A chilled, misty night hangs over the industrious mountainside city of Hupperdook, the scent of a recent rain on the air as you walk the muddied path. The nightly festivities have already begun, with the elevated section of the city known as the Idleworks Shelf alight with colorful lanterns and streamers. The distant sounds of music and firecrackers echo from hundreds of feet up the stairs of the mountain. You arrive at the quiet, dark fields of the Assembly Yard, passing massive forges and partially constructed war machines. All the city’s industry has seemingly been abandoned for the night, while the workers of Hupperdook unwind in the celebrations of the upper city.

Start by having the players describe their characters and determine which of them are traveling together. If they arrive as an established party, prompt them to talk about their collective goals in coming to Hupperdook. If they arrive as smaller groups or solo characters, play out their interactions as smaller vignettes covering how they cross each other’s paths, prompting introductions on the way to a destined meeting. Either way, point out that most activity appears to be happening in the upper city.

With the scene set, the characters can progress farther through the streets. As they do, they come across an older fellow named Auby Shudderstone (a neutral good, male gnome commoner), cleaning his open-air machinist’s workstation. The only gnome still working in the area of the Assembly Yard that the characters pass through, Auby is a bit ornery and doesn’t want to party with his fellow machinists. However, he can offer up information about the city if prompted. He’ll recommend that characters speak with Watchmaster Bram Gulchswattle for work, and will even act as a guide if treated with respect or offered coin.

When the characters are headed past the Assembly Yard into the Ironlot area of the city, proceed with the next section.

Prison Break!

Before the characters reach the stairs to the Idleworks Shelf, read:

The peace of the evening is shattered by the deafening crack of a massive explosion that rocks the southeast part of the city. At the base of the mountain, shards of rock spray the street a hundred yards from where you stand. Heavy smoke billows from a cavernous hole in the mountain wall. As you shake the ringing from your ears, six cloaked figures appear in the street, running from the source of the explosion—and charging straight toward you!

Ask each player how their character reacts. If any of the players wish to try to stop or engage with the running figures, tell everyone to roll initiative. The action begins near the mountain base of Lower Hupperdook, so see the Ironlot streets (area H1) below for more information.

Depending on their interest or sense of curiosity, the players might wish to simply step away from the intruders and allow them to escape, perhaps following them afterward. If so, they can get a good look at the figures before one of them releases a cloud of magical fog behind them, aiding their escape and making it impossible for the characters to pursue them. If the players wish to set up a trap or surprise the cloaked figures as they rush past, ask them how they choose to prepare in the few moments available to them, then begin combat once the trap is sprung.

H1. Ironlot Streets

The cloaked figures are five Kobold Underling and Sken Zabriss (see the accompanying stat blocks). They begin at the western edge of map 5.5. Having just escaped from prison, Sken has no interest in fighting to the death. Instead, she attempts to push past any interlopers to reach the northeast edge of the map and escape the city. The kobolds, however, attack anyone they perceive as interfering with their escape, shouting “No witnesses!” If two of the kobold underlings are killed or two of the characters drop to 0 hit points, the remaining kobolds and Sken focus on escaping. Sken drops a fog cloud spell behind her, and all the NPCs use the Dash action to make their exit.

Auby Shudderstone

If the characters convinced Auby the gnome to guide them through the city, they’ve inadvertently led him into a dangerous fray. Enemies attempt to strike him if he gets in their way, and the characters might need to decide between protecting their guide and focusing on the attackers.

Exploding Kobolds

If any kobold underlings are reduced to 0 hit points during the fight, the characters have only 2 rounds to investigate and loot the corpse before the body begins to emit a high-pitched whine. If a kobold was reduced to 0 hit points by a critical hit, it explodes immediately (see the Messy End trait in the kobold underling’s stat block).

A character with a bladed weapon or thieves' tools can attempt a DC 10 Wisdom (Medicine) check to remove the acorn-sized explosive from a dead kobold’s body before it explodes (see the “Alchemical Items” sidebar presented later in this chapter). On a success, the character removes the explosive and has 1 round to dispose of it or disarm it. Throwing the explosive away from creatures and structures allows it to detonate safely. A character can also use tinker’s tools to try to disarm the explosive, which requires an action and a successful DC 12 Dexterity check.

A successful DC 14 Intelligence (Investigation) check made to search a kobold reveals a deep-crimson mud staining its feet, plus a lead key hanging on a cord around its neck.

If the characters manage to subdue or capture any kobolds, their loyalty to Stahlmast is hard to break. A successful DC 15 Charisma (Intimidation) check begins to turn a captured kobold, but before it can reveal any information, crossbow bolts shot from the distant shadows (where more of Stahlmast’s loyal forces are watching) silences the would-be confessor.

Aftermath

When the fight is done, numerous citizens and members of the Crownsguard respond to the commotion, followed by the Watchmaster Bram Gulchswattle (a lawful good, male gnome veteran). Bram wants to know who the characters are and what they saw. If the characters are hesitant to answer openly, the watchmaster might take it as a sign of guilt, threatening to arrest them unless they speak plainly.

Bram might recognize the characters as adventurers by their actions in trying to stop the escaping criminals (if they did so), by their attire and equipment, or if they introduce themselves as such. Either way, he offers to hire them. He describes the runaway goliath as Sken Zabriss, a prisoner of war, but has no idea who the kobolds were. He offers a bounty of 500 gp to anyone who will hunt down and bring Sken back, as well as investigate who was responsible for breaking her out. Bram offers 250 gp up front. If the contract is accepted, he presents the characters with a copper-and-gold badge that indicates they are working under his authority. While the emblem is visible, all the characters have advantage on Charisma (Persuasion) checks made to pry information from stubborn citizens of Hupperdook.

Where To Go From Here?

The characters can travel across Lower Hupperdook to hunt down their quarry. If they ask Bram for guidance on where to look first, he points them in the direction of the smoking hole in the side of the mountain, at the site of Gearhole Prison.

H2. Gearhole Prison

If the adventurers head toward Gearhole Prison, read:

It’s easy to see the metallic sheen of many tall steel plates affixed to the mountainside—the outer walls of Gearhole Prison. Moonlight and still-smoldering fires frame the billowing smoke that pours from a gaping cavity in the rock and metal, marking the violent escape route taken by the goliath and her accomplices.

Members of the Crownsguard are on site. They try to keep the characters away from the scene, though characters can talk their way past these guards by showing their delegate emblem or convincing the guards that they’ve come to help with a successful DC 12 Charisma (Persuasion) check.

When the characters are led to the scene of the escape, read:

A ten-foot-wide hole edged with twisted steel and jagged rock opens up above a pile of rubble. Beyond the hole is a badly damaged stone prison cell, little more than soot-stained walls and an overturned bed charred on one side. A thin skylight above the hole matches others alongside it in the steel wall, and was apparently the cell’s window. A mangled chamber pot is embedded in the right wall, where a elf in a long leather coat is pulling it from the stone. She pockets three charred pieces of paper from the brass pot before turning and acknowledging your presence.

The elf asks the characters their business, and introduces herself as Yinra Emberwind (see her stat block later in the adventure), a bounty hunter who heard the commotion from the Idleworks Shelf. She brags about having already finished her work here, and wishes the characters good luck in finding Sken before she does. The characters can attempt to barter for the paper Yinra recovered, which she relinquishes for 50 gp in coins or other treasure. A character who wants to steal the paper from Yinra while she’s engaged in conversation must succeed on a DC 18 Dexterity (Sleight of Hand) check. On a failure, Yinra grabs the would-be thief’s hand and laughs at them before leaving.

If the characters procure the charred paper, they appear to be fragments of a damaged note written in clear handwriting. (Show the players handout A.)

Text from Handout A

Worry not. I am an ally of your comm….. no questions.

Take this ring and follow…. my humble domain….tand back!

Inspecting the Bed

Any character who investigates the bed confirms that it is burned only on the side facing the hole, as if used as a barrier to protect against the blast. With a successful DC 12 Intelligence (Investigation) check, they find a jagged, fist-sized shard of bronze lodged in the bed. It smells strongly of sulfur and burned blasting powder, and doesn’t match any other objects in the cell.

Inspecting the Rubble

A character who investigates the rubble confirms that the explosion came from inside the room, with most of the stone and steel having been blown out from the inside. A successful DC 12 Intelligence (Investigation) check notes signs of multiple simultaneous explosions at various points on the inside wall.

With a successful DC 14 Intelligence (Investigation) check, a character makes a discovery within the loose rock—a strange, flat automaton the size of a dinner plate. It appears to be made from iron, resembles a crab, and is damaged beyond the point of functionality. Its size means it would have fit through the skylight.

More Questions

With a few clues recovered, the characters can ask around in hopes of uncovering more of the secrets of Sken’s escape. For each specific location they travel to in search of answers, roll a d6. On a roll of 6, Yinra Emberwind is just leaving as the characters arrive, taunting them as she exits.

Use the following to guide the next steps of the characters' investigation:

• If they ask about the automaton, the characters are directed toward Master Maker Cleff Tinkertop. His shop in the Idleworks Shelf has been closed since the war picked up. The city’s leaders keep him and his daughter Rissa working on warfare designs down in the Builder’s Plot (area h3).
• If the characters ask around regarding explosives or blasting powder, helpful citizens can point them toward the city’s only sanctioned creators of such things at the Firemark Facility (area H5).
• If they ask about the deep-crimson mud seen on the kobolds' feet, none of the locals have any sense of where it might have come from, but it’s suggested that the characters might find more information at the Lay of the Land herbalist shop (area H4).
• If the characters ask if anyone saw where Sken and the kobolds escaped to, a number of people saw them running toward the north side of the city, but they eventually vanished from sight in the shadows.
• Asking about strange happenings in the city recently, a number of builders and designers complain of a growing rash of thefts. Tools, raw materials, metal ingots, and other manufacturing supplies are consistently targeted, though always in small amounts.

H3. The Builder’s Plot

If the adventurers head toward the Builder’s Plot, read:

Stepping past the outer walls of the city brings you back into the dusty expanse of the Assembly Yard. Row after row of shaded construction bays and towers flank partially built catapults, heavy cannons, and other odd, experimental weaponry encircled by metal fences. Following the directions you were given to the Builder’s Plot leads you toward high piles of metal sheeting and the sounds of incessant hammering.

During the day, the characters find Cleff Tinkertop and his daughter Rissa (chaotic good gnome Commoner) building a prototype metallic glider. If they arrive in the evening, the area is empty except for a few patrolling Crownsguard. Asking the guards about Cleff Tinkertop sees the characters directed to Sootswallow Lodge (see “Other Hupperdook Locations” later in the adventure), where he often spends his evenings after work.

Master Maker Cleff Tinkertop

Cleff is an amiable middle-aged gnome, albeit a bit absent-minded and easily distracted. Rissa is sharp and keeps her father on track as best she can. If they are asked about explosives or shown the bronze shrapnel, they direct the characters toward the Firemark Facility (area H5), the only sanctioned manufacturing den of blasting powder and black powder in Hupperdook.

If the characters show Cleff the damaged automaton, he recognizes the design as his own. Thinking at first that the device might be one of his older models, he inspects it further and scoffs at the realization that it is a poor copy. The crafting reminds him of the work of an old colleague of his—Huron Stahlmast. Talented but impatient, Stahlmast was prone to copying the work of others and executing it poorly. He hasn’t been seen in Hupperdook for years.

Treasure

If the characters are particularly interested in the functionality of the broken automaton, Cleff offers to repair it. Doing so takes a few hours and costs 15 gp for materials, whereupon the characters are the owners of a vox seeker (see chapter 6).

H4. Lay of the Land Herbalist

If the adventurers find their way to this shop, read:

Navigating the winding streets of the Ironlot, you find a wedge-shaped hutch of smoke-stained thatch and warped wood. A faded sign bearing the name “Lay of the Land” dangles above the door. Entering the shaded interior, you are greeted by all manner of smells, from pungent fungi, to dried weeds, to burning incense. A woman turns toward you where she eats at a corner table, her smiling mouth half-filled with food, her voluminous black hair framing her face.

The welcoming herbalist Zendasa (a chaotic good, female human druid) treats her customers almost as children under her care, and asks frequent and probing questions regarding the characters' daily habits and hygiene. Her shop sells the following items from chapter 5 of the Player’s Handbook: antitoxin, candles, druidic focuses, incense, healer’s kits, oil, perfume, Potion of Healing, alchemist’s supplies, and herbalism kits.

Muddy Feet

If the characters describe the stained, muddy feet of the kobolds who helped break Sken Zabriss out of prison, she tells them that red clay shouldn’t be found in Hupperdook. The most likely place for it to have come from is farther up the mountain, near the long-dormant volcanic caps of the Silberquel Ridge.

H5. Firemark Facility

When the adventurers arrive at the Firemark Facility, read:

This brown-and-red brick building is larger than you expected, its black-iron roof stretching over a massive compound. The scent of sulfur and blasting powder, familiar from the prison cell, is faint on the air here. As you draw near, a gnome guard approaches you with a suspicious look.

The gnome guard does her best to shoo the adventurers away from this restricted site. The characters can sway her with a 15 gp bribe, or can attempt to talk their way past with a successful DC 14 Charisma (Deception or Intimidation) check. Once inside, they can speak with the site’s blast gaffer, Sleese.

Blast Gaffer Sleese Firemark

Sleese Firemark (a lawful neutral, male gnome commoner) is a hotheaded fellow who seems intent on working himself into an early grave. He isn’t happy about having his workflow interrupted but entertains questions from the characters for a few moments.

If the adventurers inquire about any missing blasting powder, Sleese denies that any such thing could happen, checks his ledgers, and confirms that all is accounted for. He touts the rather impressive guard force that watches over the facility and the importance of the work done there with the escalating need to overpower the Kryn. He might also lament that the facility’s most talented powder artisan has been out ill for a few weeks.

A Missing Master

If asked about the ill artisan, Sleese mentions that a gnome named Nima Cinnarid had been one of the Firemark Facility’s most diligent suppliers of raw materials and most skilled crafters of high-quality blasting powder, at least until she took ill three weeks ago. She’s been holed up in her house in the northern part of the Ironlot ever since. A few of her Firemark compatriots have tried to visit her, but she won’t let anyone in. Sleese is noticeably fearful over how bad this illness might be.

Treasure

Sleese offers a pouch of blasting powder (see the “Alchemical Items” sidebar later in the adventure) as a gift if the characters agree to check in on Nima Cinnarid. He can direct them to her house at area H6.

H6. Nima Cinnarid’s House

This encounter location is shown on map 5.6. If the characters seek out Nina Cinnarid at home, read:

Traveling to the north end of the Ironlot, you approach the humble abode that Sleese Firemark directed you toward. The green-painted wooden walls are streaked with dirt washed down by the rain. A sign hanging on the front door reads: “Sickness within. Do not disturb.” Curtains at the windows all appear to be closed.

The front and side doors to the house are locked, but can be picked with a successful DC 15 Dexterity check using thieves' tools. Knocking once on the front door yields no answer, but a second knock summons a coughing, creaky voice from the other side that falteringly tells the characters to stay away for fear of catching the sickness. Any character with a passive Wisdom (Insight) score of 15 or higher, or who is successful on a DC 15 Wisdom (Insight) check, recognizes that the voice is nervous—and is definitely not a female gnome.

If the characters mention anything about the prison break, the voice pauses, then states, “Actually, I think I might know something about that.” As the front door is unlocked, the voice invites the characters in.

The interior of Nima Cinnarid’s house is dark except for a guttering candle on the back table, shedding dim light in a 5-foot radius. Four Kobold Underling lie in wait in the shadows. Any character with a passive Wisdom (Perception) score of 16 or higher, or who succeeds on a DC 16 Wisdom (Perception) check, sees the kobolds hiding and ready to spring. When any character moves more than 10 feet into the house, the kobolds attack. Anyone who was not aware of the hidden kobolds is surprised.

When the kobolds are defeated, the characters have 2 rounds to loot or investigate the corpses of any slain kobolds. After that time, the kobolds' bodies explode as in area H1. See the “Exploding Kobolds” section in that area, the kobold underling stat block (earlier in the adventure), and the “Alchemical Items” sidebar for information on removing and keeping the Explosive Seed the kobolds carry.

As in area H1, a successful DC 14 Intelligence (Investigation) check reveals that each of these kobolds has a deep-crimson mud staining its feet, plus a lead key hanging on a cord around its neck. Neither of these things can be discovered if a kobold explodes.

Development

If the characters manage to subdue a kobold, it gives up what it knows with a successful DC 15 Charisma (Intimidation) check. The kobold can reveal that it works for someone called “the Master,” and that Nima Cinnarid has been kidnapped and is presently held high up the mountain at a location called Silver Falls. If its life is spared, the kobold promises to guide the characters to the Silver Falls cavern area. The kobold accompanies the party through the “Mountain Climb” section below but attempts to escape at any opportunity.

Signs of Trouble

Any search of the house reveals signs of a struggle from a few weeks past, including broken furniture and an emptied chest with a broken lock. A few heavy coats and sets of work boots sized for a gnome are all stained with red dirt. A broken worktable has been dumped into a corner strewn with scraps and garbage. Searching through the refuse reveals a number of torn parchment notes, one of which provides a clue to the location of Silver Falls. (Show the players handout B.)

Treasure

Characters who sift through the wreckage find a pouch of blasting powder (see the “Alchemical Items” sidebar).

Text from Handout B

Of all the sources we mine from within the Silberquel, my yield of saltpeter still proves the most pure and powerful! The Firemarks, pry as they might, will have to respect my expertise and contributions to the war effort.

The sheer volume of untapped guano in that cavern behind the top of the falls is invaluable, and once I have enough marked interest from the Firemark Facility, I’ll let them help in harvesting my secret cave.

Other Hupperdook Locations

The following miscellaneous locations are minor areas the characters might visit in Hupperdook during their investigations.

H7. The Prayer Foundry

A majestic temple to Moradin the All-Hammer, this mighty octagonal structure resembles a massive anvil atop an iron shrine. Within, holy symbols and prayer coins are pressed and forged, while blacksmiths and tinkerers come to have their plans and creations blessed.

H8. Omnismelter

Attached through a series of angled hallways, this network of foundries forms a sprawling compound that smelts, purifies, and prepares a majority of the metal materials and ingots distributed throughout the Marrow Valley.

H9. Neverbend Smithy

Long run by the Neverbend family of gnomes, this is the place to go for arms and armor, as well as general smithing needs. Standard metal weapons and armor, as well as metal-based adventuring gear, can be purchased here.

H10. Ironside Barracks

Built across from Gearhole Prison, this squat, metal-reinforced barracks is home to most of the Crownsguard and Righteous Brand soldiers stationed in Hupperdook. Watchmaster Bram Gulchswattle can often be found here.

H11. Sootswallow Lodge

The largest (and one of the only) taverns operating below the Idleworks Shelf, the Sootswallow Lodge caters to the builders and makers of the Ironlot during work hours, then plays home to the sketchier elements of Hupperdook by night. A fence named Udoth who keeps a room here in the evenings is always in the market for adventuring goods, which he buys for 75 percent of their value rather than 50 percent.

H12. The Armavault

A majestic 30-foot-high steel door sits flush with the rocky wall of the mountain here. Beyond the door, a heavily guarded interior hall expands into a long corridor lined with massive alcoves housing stored siege weapons.

H13. Silberhaul Mines

This gated courtyard contains the many entrances to the deep tunnels and ore veins of the Silberhaul Mines.

H14. Winch Lift

These giant steel platforms lifted by impressively large chains carry heavy equipment and large groups of people between the Ironlot and the Idleworks Shelf.

H15. Upper Hupperdook

The upper part of the city is divided into two main sections—the Idleworks Shelf and Silver Falls Grove. The Idleworks Shelf is a largely recreational district that houses the city’s evening celebrations, and is home to the empire-renowned Blushing Tankard tavern. Wrapped around the waterfall lake that gives it its name, Silver Falls Grove is the residential core of Hupperdook, its streets dense with elevated stone-and-metal towers that house families at every level.

Alchemical Items

This adventure features two new alchemical items, each described below.

Blasting Powder. This volatile alchemical powder comes in a small pouch. When ignited by an open flame or a fuse, the powder explodes. Each creature within 5 feet of the exploding pouch must make a DC 13 Dexterity saving throw, taking 3d6 bludgeoning damage on a failed save, or half as much damage on a successful one.

A character can bind multiple pouches of blasting powder together so they explode at the same time. Each additional pouch increases the damage by 1d6 (maximum of 10d6) and the blast radius by 5 feet (maximum of 20 feet).

Explosive Seed. This acorn-sized sphere of brass contains a small amount of blasting powder and a clockwork trigger. An explosive seed can be thrown up to 30 feet as an action, detonating on impact. Each creature within 5 feet of the exploding seed must make a DC 10 Dexterity saving throw, taking 1d8 bludgeoning damage on a failed save, or half as much damage on a successful one.

Ascending the Mountain

As the adventurers leave Hupperdook to climb up the Silberquel Ridge toward the top of the Silver Falls, read:

You leave the smoky atmosphere of the city for cleaner mountain air as you begin your hike up the treacherous heights of the Silberquel Ridge. The steep climb grows more and more precarious as you go, with pathways becoming thin and hard to traverse among the cliff-side trees and gray rock of the mountainside. You keep the silver line of the tumbling waterfall always in your sights, a guide toward your hopeful destination.

The mountain pass is rugged but its paths are easily navigable, requiring no ability checks to climb. Ascending to the peak of the Silver Falls at an average pace normally takes six hours. A successful DC 14 Wisdom (Survival) check locates recent kobold tracks leading up the mountain, cutting that travel time in half. For each hour of travel, roll a d8 and consult the Random Mountain Encounters table to see if any denizens of the mountain cross paths with the characters. If you roll the same encounter twice, reroll. You can alternatively select an encounter (or multiple encounters) to liven up the characters' journey.

Random Mountain Encounters

Peak of Silver Falls

When the characters finally reach the peak of the Silver Falls, read:

The sound of rushing water grows louder as you finally reach the top of the Silver Falls. The impressive flow of water cascades down the mountainside toward Hupperdook below. Around the crest of the falls, the rocky earth is a deep, rich red.

With the information revealed in the note recovered in Nima’s house (area H6), the characters have no trouble spotting telltale shadows behind the waterfall that hint at a hidden cavern. Any investigation of the area reveals a 10-foot-wide rock shelf covered in red mud that leads behind the falls and into the cavern beyond.

Fool’s Entrance

Any character with a passive Wisdom (Perception) score of 17 or higher, or who succeeds on a DC 17 Wisdom (Perception) check, spots a faint column of smoke rising above the waterfall. Characters who continue the mountainside climb discover a hidden, 3-foot-wide iron chimney rising from the rocky ground. The chimney is too smooth to be climbed except with a rope anchored to the rocks above. It descends 30 feet before it splits into three chimneys leading to the kitchen (area L6), the smithy (area L14), and the clockwork forge (area L19).

Any character who tries to descend the chimney without a rope or a climbing speed inevitably falls. Roll a d3 to determine which lower chimney the character tumbles down. At the end of the fall, the character must succeed on a DC 12 Dexterity saving throw or take 1d6 bludgeoning damage. In addition, the fire at the bottom deals damage to creatures that come in contact with it, as noted in each area’s description.

Silver Falls Cavern

When the adventurers enter the cavern behind the waterfall (shown on map 5.7), read:

Beyond the rushing spray of water is a dry cavern. Multiple lanterns shed light across the rocky interior, revealing a floor thickly strewn with dried bat guano, a small tent and table, a steel door set into the far wall, and two wide workbenches. A female gnome is working at the farthest bench, shackled to a chain set into the rock wall. Four kobolds sit around the table near the tent, playing a dice game with a familiar-looking gray-skinned goliath.

The bats that long dwelled in this cavern (the source of the guano from which Nima Cinnarid extracts saltpeter for creating explosives) fled when the kobolds took up permanent occupation of the cave. Characters trying to sneak through the waterfall and into the cavern must succeed on a group DC 16 Dexterity (Stealth) check to enter unnoticed, allowing them to attack with surprise. If the group check fails, Sken sees the intruders, complains about her card game being interrupted, and initiates combat.

Cavern Fight

Four Kobold Underling and Sken Zabriss all attack the characters (see their stat blocks earlier in this adventure). Sken loudly taunts them for how they’re all about to die, and shouts that the fall of the Dwendalian Empire at the hands of Xhorhas is imminent. If the characters were guided by a captive kobold from Nima’s house, it rushes to the other kobolds if it can, borrows a weapon, and joins the fray.

The shackled gnome is Nima Cinnarid, a neutral good, female gnome commoner. She hides beneath her workbench when combat breaks out, but if a kobold or Sken moves within 30 feet of the bench, read:

From under the bench, the shackled gnome grabs a handful of small brass spheres piled nearby. “You wanted these made?” she shouts. “Well, here! You can have them!”

Nima throws an explosive seed (see the “Alchemical Items” sidebar earlier in this adventure) at whichever enemies are closest, then throws another seed on each of her turns until she runs out of seeds. She has a total of four explosive seeds.

If any of the characters speak to Nima and offer her help, Sken rushes over to take the gnome hostage, threatening to kill her unless the characters drop their weapons. If the characters don’t comply and can’t stop Sken in time, the goliath attacks Nima.

If Sken is reduced to 11 hit points or fewer, she attempts to use her ring of obscuring and flees to the steel door. She spends her action pulling out a lead key she carries and opening the door, and it takes another action to close and lock it behind her. If Sken escapes, the characters need to pursue her into Stahlmast’s lair to complete their contract with Bram Gulchswattle.

Development

If the battle is won and Nima survives, the characters can free her from her shackles and learn a number of details regarding what’s going on. The gnome can offer up the following information in response to the characters' questions:

• Nima has long been a munitions expert, developing refined explosives and weapons for the war effort against the Kryn Dynasty.
• The cave is a secret source of potent explosive materials, and she has harvested guano from it for years. She normally comes here once every four to six months to stock up.
• Nima’s last trip three weeks ago ended with her capture by the kobolds and their master, Huron Stahlmast. A former engineer for the Dwendalian Empire, Stahlmast was shamed for his imperfect designs and immoral experimentation. He left Hupperdook years before and was assumed to have found his fortune elsewhere. Instead, he’s been building a lair beyond the waterfall cavern, sealed off behind the steel door.
• Stahlmast imprisoned Nima in the cavern and has been forcing her to produce explosive devices. One of those devices was used to help Sken break out of Gearhole Prison. She has also been working on plans for larger explosive devices whose purpose she doesn’t yet know.
• Stahlmast is bent on vengeance against the empire—and against the city of Hupperdook and its people.

If Nima was killed, the characters can seek this information from Sken or a captured kobold. If the fight in the cavern left no enemies or allies alive, you can move these revelations to an NPC in Hupperdook who recognizes the explosive seeds as Stahlmast’s work.

Steel Door

If any character investigates the steel door, read:

The eight-foot-tall steel door has layered crossbars and supports are embedded deep into the rock of the mountain, creating an impassible entrance to whatever lies beyond.

If the characters want to try to open the door right away, see the next section of the adventure (“Stahlmast’s Lair”) for more information.

Treasure

After defeating Sken, the characters can claim her ring of obscuring (see chapter 6). The workbench Nima was working at holds 1d4 + 1 Explosive Seed (see the earlier “Alchemical Items” sidebar).

Character Advancement

At the end of this part of the adventure, the characters all reach 2nd level. The setup for the next part of the adventure assumes that the characters return to the city before seeing what lies beyond the steel door. If Nima survived the fight, she is anxious to flee the cavern and begs the characters to escort her back to Hupperdook.

If the players want to press on immediately—especially if both Nima and Sken were killed—that’s fine. Just make sure all the characters have leveled up, and let them take a long rest in the cave before moving on to the next part of the adventure (“Stahlmast’s Lair”). You can then rework the events below when the characters return to Hupperdook after having bested Stahlmast in his lair.

Next Moves

If Sken was left alive after combat, the characters can use the chains that once shackled Nima to bind the goliath. Taking her or her corpse back to Watchmaster Bram Gulchswattle at Ironside Barracks (area H10 in the first part of the adventure) completes their contract and allows them to collect their reward. The characters can then take some time to rest and handle any business they might wish to conduct in Hupperdook.

You can read or paraphrase the following text to complete this part of the adventure:

With a successful mission behind you and your hard-earned reward paid out, you have a chance to give more thought to the steel door you saw behind the waterfall—and the nefarious plots that Stahlmast is hatching to punish the fair people of Hupperdook.

With the completion of this first part of the adventure, the players are free to decide what’s next for the characters. They can leave the threat of Huron Stahlmast to the authorities as they move on to another adventure elsewhere, or they can talk to Bram Gulchswattle about extending their contract to include a bounty for Stahlmast. Gulchswattle is prepared to pay the group an additional 1,500 gp for the capture or elimination of Stahlmast, along with evidence of his wrongdoing.

Whatever drives the characters' decision to go after Stahlmast, the next part of the adventure begins at the steel door that leads into Stahlmast’s lair.

Stahlmast’s Lair

Once the players are ready to explore Stahlmast’s lair, read or paraphrase the following:

Gathering your weapons and your grit, you prepare for another hike up the Silberquel Ridge. Your goal is to gain access to the lair of this Stahlmast beyond the steel door—and to uncover the full scope of his mysterious plans.

You might use the Random Mountain Encounters table (from earlier in this adventure) during the characters' ascent, or you can decide that their familiarity with the mountain trails makes it easier to avoid trouble. Either way, having made the journey already, it takes only three hours to reach the Silver Falls.

Steel Door

If the characters recovered an undamaged lead key from any of the kobold minions or Sken, they can easily unlock the door. Otherwise, it can be opened with a successful DC 20 Dexterity check using thieves' tools. Savvy players might also think to try blowing the lock open with blasting powder. Doing so requires one pouch of blasting powder, tinker’s tools, and a successful DC 12 Intelligence check, but alerts Stahlmast and his minions to the characters' approach.

Entering the Lair

When the characters move beyond the steel door, read:

The shadowed tunnel stretches onward for fifty feet before the orange glow of lantern light sets an ominous glow across its rough stone walls. The smell of burned coal, wet earth, and refuse hangs heavy here. From a distance comes the intermittent echo of rough, conversational kobold barking. The tunnel splits ahead, with one branch running south and the other continuing on to a cavern that is the source of the light.

Stahlmast’s Minions

Even kobolds as well trained as the ones that serve Stahlmast prize self-preservation over all else. In each encounter with Stahlmast’s kobold minions, if half or more of the kobolds are defeated or killed, any remaining kobolds flee the battle. Fleeing kobolds retreat deeper into the lair in hopes of warning Stahlmast and seeking reinforcements.

If any kobolds are captured and questioned, they reveal what they know of Stahlmast’s operation with a successful DC 13 Charisma (Intimidation or Persuasion) check. You can have individual kobolds know only bits of the overall plan so that the characters learn all the information only over time:

• The Master is planning to make many tiny metal crabs (Vox Seeker, as described in chapter 6).
• The gray dwarf is obsessed with his ugly statue.
• The scary elf visits every few weeks to train the kobolds, and then vanishes into the Master’s fire room.

Making a Scene

Though the winding passages of the compound help mute the sounds of footsteps, loud noises (including combat or shouting) alert the lair’s inhabitants of intruders at your determination.

Voice of Stahlmast

Each area of the lair is outfitted with a metal speaking tube that protrudes from the ceiling, and which Stahlmast uses to issue orders wherever he happens to be. If a character speaks into a tube, their words are heard in all areas of the lair.

If Stahlmast is aware of the characters' intrusion, he occasionally taunts them through these tubes. His remarks alternate between threatening and mocking, boasting about his plans while goading the characters into finding him—and trying to lead them into traps and ambushes. As characters approach the clockwork forge in area L19, he might start describing the benefits of joining him.

All Is Not Lost

If the characters lose the fight in the Silver Falls cavern or in any part of Stahlmast’s lair, it doesn’t necessarily mean the adventure is at an end. Whenever Stahlmast’s minions get the upper hand, you can have them start knocking characters out rather than killing them. Unconscious survivors of a fight wake up in a holding cell in area L7 of Stahlmast’s lair, stripped of their equipment. Any new characters replacing fallen characters can join them there as previously captured prisoners.

The characters' confiscated equipment is in a chest in the armory (area L2), and a confident kobold underling guards their cells. You can then set up a scenario in which the characters find a way to escape and recover their equipment.

L1. Turret Cavern

This natural cavern is reinforced by support beams across its fifty-foot length. A smooth pillar of stone rises in the center of the cave to a height of eight feet, nearly touching the ten-foot-high ceiling. The tunnel continues beyond the cavern, curving abruptly to the west and out of sight.

Any character with a passive Wisdom (Perception) score of 16 or higher, or who succeeds on a DC 16 Wisdom (Perception) check, notices that a hand crossbow is mounted to the top of the stone pillar. This clockwork crossbow remains inert unless Stahlmast is aware of the characters, in which case it attacks the nearest creature within 30 feet of it each round. The crossbow is +5 to hit and deals 3 (1d6) piercing damage on a hit. If a 1 or 2 is rolled for the crossbow’s attack roll, it breaks and no longer functions.

The crossbow turret is Large object with AC 17, 15 hit points, and immunity to poison and psychic damage.

L2. Armory

Three long tables occupy the center of this square cavern, a lantern dangling above them. The walls are adorned with hooks and loops that hold digging tools and basic weapons in a disorganized fashion. A large chest is set beneath one table, and a door stands closed to the north.

A kobold underling (see the stat block earlier in this adventure) sits at one of the tables as the characters approach this area, cleaning a pile of soiled tools and weapons with a rag as it curses under its breath in Draconic. If it receives any warning that intruders are coming (including hearing the characters fighting or talking in area L1), it might make a brief stand against them—or it might flee before they arrive, leaving its work behind.

The north door into area L3 is locked. Roguun the duergar blacksmith (area L14) has the key, or the lock can be picked with a successful DC 18 Dexterity check using thieves' tools.

Recovered Goods

If the characters were captured and thrown into the prison cells in area L7, their weapons hang on the walls here and their other equipment is in the chest beneath the table. Yinra Emberwind equipment is also stored there (see area L7).

Treasure

Characters looting this area can claim four daggers, five shortswords, three spears, three crossbows with forty bolts each, and two sets of thieves' tools.

L3. Volatile Materials Storage

Short steps lead down into this small cavern, whose air is heavy with the smell of sulfur. Numerous boxes and barrels are filled with blasting powder, black powder, and other dangerously explosive materials.

This cavern is extremely dangerous. Any open flame brought into the area (including that of a torch), as well as any fire or lightning-based effect used in the area, has a 30 percent chance of detonating the materials stored here. This detonation deals 4d10 bludgeoning damage to each creature within the room and in the armory (area L2). It also partially collapses this cavern and alerts every creature within the lair to the characters' intrusion.

Any character with a passive Wisdom (Perception) score of 13 or higher, or who succeeds on a DC 13 Wisdom (Perception) check, notices that the materials are stored unsafely and assesses that it’s a miracle none of it has exploded yet.

Treasure

The characters can claim up to twenty pouches of blasting powder (see the “Alchemical Items” sidebar, earlier in this adventure) from this area.

L4. Recreation Room

Flickering lanterns illuminate this spacious cavern, which features three tables surrounded by chairs. Three kobolds are sitting around the central table, playing cards for copper pieces. Mugs and scattered piles of playing cards litter the blade-scarred tabletops. A dozen small cloaks hang on the walls from metallic hooks. A passage to the south bends out of view, while rickety wooden doors obscure a cavern to the west. Another door on the north wall is partially ajar, while a passage to the northeast leads toward a dark cavern.

The three Kobold Underling (see the stat block presented earlier in this adventure) playing cards are engrossed in their game. If the characters observe the game unnoticed, it quickly becomes apparent that the kobolds aren’t following any consistent rules. The kobolds attack as soon as intruders are spotted.

Treasure

Small characters—or Medium characters who crouch down—can don the cloaks found here. Doing so grants advantage on Charisma (Deception) checks to characters trying to pass themselves off as kobold minions, as long as they remain 30 feet or more away from any ally of Stahlmast.

L5. Stahlmast’s Workroom

From the inclined passage leading to this rectangular cavern, you see a heavy lantern hanging from the ceiling, shedding bright light. A long table in the cavern is covered in large sheets of parchment, books, inkwells, and charcoal, and numerous notes are spiked to the stone walls.

Most of the notes here read like mad scrawls mixed with engineering designs. Sketches of the layout of Hupperdook and the mountaintop are seen, as well as what looks like the designs for Explosive Seed (see the “Alchemical Items” sidebar earlier in this adventure) and a diagram of how the seeds can be surgically implanted into creatures. Another note details the process by which sharks are to be placed into the waterfall lake in Silver Falls Grove. One strange design shows what appears to be some kind of clockwork-powered armor.

Vox Seeker

Clinging to the underside of the table is a vox seeker (see chapter 6). There is a 25 percent chance that the automaton is wound up when discovered, allowing it to attack for up to 5 minutes.

Dastardly Deeds

A character who studies the notes and diagrams can determine that Stahlmast plans to set powerful explosives across the mountainside in a way that will bury most of Hupperdook in a landslide, even as it leaves his lair intact. Bringing these designs to Watchmaster Bram Gulchswattle earns the characters an additional reward (see “Concluding the Adventure” at the end of this adventure).

Secret Door

Any character with a passive Wisdom (Perception) score of 17 or higher, or who succeeds on a DC 17 Wisdom (Perception) check, notices a thin slab of rock that hides a hidden passageway. This passage leads into Stahlmast’s bedroom in area L18.

L6. Kitchen

Beyond the rickety wooden doors, a rough-walled cavern serves as a kitchen. A cutting block to the north is stained with old blood, while a low-burning fire to the south heats a cauldron hanging by chains. A thick, foul-smelling soup simmers within the cauldron.

Two kobolds are hard at work here, one cutting gamy meat at the chopping block, the other stirring the soup in the cauldron.

The two Kobold enjoy kitchen duty and flee if attacked.

Fire

A smoky fire heats the cauldron. A creature that enters the fire for the first time on a turn or starts its turn there takes 3 (1d6) fire damage.

Chimney

A 3-foot-wide iron chimney rises above the cauldron, eventually leading outside the mountain (see the earlier “Ascending the Mountain” section for more information).

L7. Prison Cells

This dank, dreary cavern is sectioned off by walls of iron bars that divide the area into two cells. Seated on a small chair against the west wall is a kobold.

The bounty hunter Yinra Emberwind is currently locked in the east cell, stripped of her equipment. (See her stat block earlier in this adventure, but she is AC 13 without armor.) A kobold underling (see its stat block earlier in the adventure) sits in the chair when the characters first arrive, watching the prisoner. The kobold carries keys that open both cells, or the locks on the cells can be picked with a successful DC 18 Dexterity check using thieves' tools.

If Yinra is freed and no other immediate threats are nearby, she tries to immediately escape the lair. The characters can persuade her to stay and help them with a successful DC 12 Charisma (Persuasion) check. Either way, Yinra speaks of her fear that Stahlmast is planning a deadly attack against Hupperdook.

Stahlmast’s Lair (areas L8-L14)

L8. Shark Chamber

The passageway straightens into a square-walled cavern some forty feet long and twenty feet wide. The floor is covered in iron, and the rocky ceiling stands ten feet high. Beyond the iron floor, the passageway turns back to rough stone and turns to the north.

With a successful DC 12 Intelligence (Investigation) check, a character notices that the iron floor is set with a groove at its center, bisecting it lengthwise. If more than 50 pounds of weight is placed on the iron floor, it splits open and its two halves swing down, revealing a 10-foot-deep pool of water 5 feet below where three hungry Reef Shark are waiting. The floor resets automatically, snapping shut after being open for 1 minute.

Each creature standing on the iron floor when it opens must succeed on a DC 13 Dexterity saving throw to grab onto the wall and avoid tumbling into the water below. A creature can try to avoid falling into the shark-infested pool by staying close to the wall; it must succeed on a DC 10 Strength (Athletics) check for every 10 feet it moves or tumble into the pool.

L9. Training Room

Within this cavern, seven wooden training dummies stand against the walls, all of them nicked and splintered. Heavy sand is strewn across the rocky floor, while blunted weapons and shields lean against the walls

A dark elf stands in the middle of the room, shaking his head and watching with a faint look of disgust as four kobolds spar with one another.

When the characters first arrive here, four Kobold are being trained by Ishel—a drow ambassador from the Kryn Dynasty. Ishel uses the drow stat block but has 24 hit points, which raises his challenge rating to 1/2 (100 XP). He carries keys to the chest in area L10 and to the secret door in area L19.

If Ishel is reduced to 12 hit points or fewer, he attempts to flee through area L20 and alert Stahlmast about the intruders. If he is captured and questioned, the drow warns the characters of the steam trap in area L12. If pressed hard, he might mention that he belongs to Den Hythenos of the Kryn Dynasty, which has an agreement with Stahlmast. He can also tell the characters about the path to the Underdark in area L20.

L10. Ambassador’s Bedroom

The smell of incense is sharp as you enter this clean and well-organized chamber. A comfortable bed is tucked against one wall, while a small table rests under a mirror against the other. A wooden armor rack stands empty in the corner.

Ishel (see area L9) is quartered in this area. Any character who looks beneath the bed discovers a long, locked iron chest there. Ishel carries the key, or the lock can be picked with a successful DC 15 Dexterity check using thieves' tools.

The chest is also trapped, which can be noted with a successful DC 14 Intelligence (Investigation) check. The trap can be disabled with thieves' tools and a successful DC 14 Dexterity check. If the trap is not disabled and the lock is picked, opening the chest causes a loud shrieking noise to blare for 3 rounds, alerting creatures in areas L9 and L11 if they have not already been dealt with. Opening the chest with the key doesn’t trigger the trap.

Treasure

The chest holds 5 pp, 113 gp, 15 sp, and 10 cp, as well as a dark steel +1 shortsword.

L11. Kobold Barracks

This spacious cavern is heady with the pungent scent of mildew. The stony floor is covered with more than a dozen bundles of moldy leather, stained fabric scraps, and torn pillows that serve as kobold beds. Three of the beds have kobolds sleeping in them.

If the characters have made a lot of noise in any nearby caverns (including by opening the chest in area L10 or fighting in area L9), the three Kobold are pretending to sleep and have their weapons hidden. A successful DC 12 Wisdom (Insight) check uncovers their ruse. Otherwise, any character who approaches within 10 feet of the sneaky kobolds causes all three to leap up and attack.

L12. Steam Trap

A roughly diamond-shaped cavern opens up beyond a set of double doors. Each of its four walls holds a three-foot-by-three-foot iron plate, mounted at the center of the wall and featuring a three-inch-diameter hole cut through the plate and the rock behind it. Across the cavern, another set of double doors stands closed.

The holes in the walls extend 1 foot in, then angle downward, preventing the mechanisms of the trap from being seen. This chamber does nothing as long as the characters have not yet caught Stahlmast’s notice. However, if he has been alerted to their presence, both sets of double doors swing shut and lock tight once all the characters (or a majority of the characters if some are hanging back) have entered. The locks on both sets of doors can be picked with a successful DC 16 Dexterity check using thieves' tools, or the doors can be forced open with a successful DC 16 Strength check.

With the doors locked, Stahlmast taunts the characters via the speaking tube in the ceiling before filling the chamber with scalding hot steam from the holes in the wall plates. Each creature that starts its turn in the steam takes 2 (1d4) fire damage. If all four steam holes are plugged up with cloth or some similar material, the trap stops dealing damage, and instead backs up and deals 4d4 fire damage to the Stahlmaster in the clockwork forge (area L19).

L13. Blacksmith’s Chamber

Tucked off to the side of the passageway is a modest bedroom containing a firm mattress, a bare table, and a small, partially sculpted stone statuette. A chair is tucked against the table, and a pile of broken rocks sits against the wall beneath it.

The small sculpture on the desk is a mostly finished representation of a dwarf, expertly carved. Any inspection of the pile of broken rocks under the table reveals them to be previously failed attempts at the same sculpture.

Treasure

Even unfinished, the statuette is worth 5 gp. Characters who search the room thoroughly find a small sack of gems hidden under the bed mattress—four opals (25 gp each), a flawed ruby (75 gp), and a flawed diamond (100 gp).

L14. Smithy

This cramped, uncomfortably hot chamber is outfitted for a blacksmith, featuring a glowing forge, an anvil, and a water trough. Various tools are set around the anvil, while piles of metal ingots stand beside the entrance.

The blacksmith, Roguun (a lawful evil, male duergar), is hard at work when the characters first enter this area. He attacks intruders at once but flees to join Stahlmast in the clockwork forge (area L19) if he is reduced to 11 hit points or fewer. Roguun carries the keys to the volatile materials storage cavern (area L3).

If a character possesses the small statue from area L13 and threatens to smash it, Roguun halts his aggression and refrains from fleeing while he attempts to barter for its safety. A character holding the statuette has advantage on Charisma checks made against the duergar. If he is captured and questioned, Roguun might mention the explosives locked away in area L3, and might also mention the secret door that Stahlmast had him install in area L5.

Forge

Any creature that enters the open forge for the first time on a turn or that starts its turn there takes 7 (2d6) fire damage.

Chimney

A 3-foot-wide iron chimney rises above the forge, eventually leading outside the mountain (see the earlier “Ascending the Mountain” section for details).

Treasure

A set of smith’s tools rests by the anvil.

Stahlmast’s Lair (areas L15-L20)

L15. Storage Chamber

Piles of metal ingots, textiles, and other materials fill this cavern, most of it disorganized and all of it clearly coming from outside the lair.

The goods and raw materials here are worth 250 gp, but the hoard weighs over two thousand pounds and has all been stolen from Hupperdook, preventing it from being resold there. If the characters notify Bram Gulchswattle of the stolen goods and their location, the watchmaster rewards them with an additional 150 gp.

Treasure

Characters who search the room thoroughly find a potion of healing.

L16. Infirmary

A row of rough, bloodstained beds outfit this makeshift infirmary. Soiled cloths have been tossed in one corner, and a door stands closed to the northwest. A kobold sleeps soundly in the bed farthest from the entrance.

The sleeping kobold underling (see its stat block earlier in the adventure) has its chest wrapped with bloodstained bandages. If the sore and scared kobold is woken up, characters have advantage on Charisma checks to question it (see “Stahlmast’s Minions” at the beginning of this section). In addition to any other information you want to reveal, the kobold complains about the pain in its chest. (Stahlmast recently implanted an explosive seed inside the kobold.)

L17. Surgery

The smell of acrid chemicals and rusting metal are pungent within this dark cavern. Two small tables against the far walls hold all manner of surgical tools and knives, as well as a tattered notebook. Beneath an unlit lantern hanging from the ceiling, a larger rectangular table is affixed with restraints and stained with old blood.

The notebook on the side table builds on some of the notes the characters might have found already in area L5. They describe in gory detail the process by which Stahlmast performs the experimental surgery that implants explosive seeds in his minions.

Treasure

A search of the room reveals a small box under one of the tables that holds 1d4 Explosive Seed (see the “Alchemical Items” sidebar earlier in this adventure).

L18. Stahlmast’s Bedroom

This smooth-walled chamber is lavishly furnished and decorated compared to the rest of the lair. Its floor is covered in a thick carpet, and it holds a large, luxurious bed, an armoire, a vanity mirror, and a small bookshelf.

The armoire holds five sets of fine clothing, one of which has a Sending Stones in its pocket. The stone can be found with a successful DC 12 Wisdom (Perception) check, or by anyone putting on the clothing. If the stone is activated, a voice responds in a thick accent, asking “What is it you need?” A successful DC 12 Intelligence check reveals the accent to be Xhorhasian. No matter what the response of the character using the stone, they must succeed on a DC 18 Charisma (Deception) check or the agent with the other Sending Stones recognizes that the stones have been compromised. The other stone is then destroyed, severing the connection.

Secret Door

Any character with a passive Wisdom (Perception) score of 17 or higher, or who succeeds on a DC 17 Wisdom (Perception) check, notices a thin slab of rock that hides a hidden passageway. This passage leads into Stahlmast’s workroom (area L5).

Treasure

A locked chest is hidden beneath the bed, and can be opened with thieves' tools and a successful DC 16 Dexterity check. The chest holds 170 gp, 65 sp, and two Potion of Healing. It also contains a letter written in Undercommon, which promises that more support and minions will soon be sent through the tunnel. The letter thanks Stahlmast for his soon-to-be fruitful alliance with Den Hythenos of the Kryn Dynasty. Turning the letter over to Watchmaster Bram Gulchswattle earns the characters an additional reward (see “Concluding the Adventure” at the end of this adventure).

L19. Clockwork Forge

Huron Stahlmast (a lawful evil human cultist wearing goggles of night) awaits the characters in this elaborate workshop. If the drow ambassador from area L9 or Roguun from area L14 escaped earlier encounters with the characters, he has joined Stahlmast here for the final fight.

When the characters can see into this area, read:

A mighty anvil of dark metal rests in the center of this cavern between two rocky pillars. To the south stands a semicircular pool of stagnant water. Numerous tables line the cavern walls, piled with partially constructed mechanical devices and motionless automatons. A massive forge stands along the north wall, filling the cavern with a bright orange glow. A dangerous-looking clockwork construct rests in front of the forge, resembling a skeletal iron statue without a head.

A sweaty, pallid human of middle years is climbing up the side of the construct. He then slips down inside it, as if donning a monstrous suit of armor.

If the characters have managed to get this far without Stahlmast being alerted, he shows momentary surprise when he sees them, but his bravado quickly takes over. Either way, as soon as Stahlmast becomes aware of the characters, read:

The human addresses you with a wily grin as he puts on a pair of goggles. “You’ve certainly proven capable and determined by getting this far. I appreciate those traits immensely, and they should be rewarded. Work with me and my team. Help us correct the addled vision of Hupperdook’s future and the future of this wretched empire. Wealth and power await those who prove useful to the destined victors of this war. What do you say?”

Stahlmast has no qualms about whom he works with, as long as those who serve him understand that he’s in charge. He might appeal to the characters as free adventurers, hoping to convince him that fighting against the Dwendalian Empire is a noble cause, or he might appeal to their greed, talking of how much wealth might be gained by breaking the empire’s power.

If the characters abandon their pledge to aid Hupperdook and instead agree to Stahlmast’s offer, they are granted a room of their choice within the lair and a weekly pay of 25 gp as his elite enforcers. The characters reach 3rd level (see “Concluding the Adventure”), but their path now leans toward working with the Kryn Dynasty and helping Stahlmast with his plots against Hupperdook and the Dwendalian Empire.

Alternatively, the characters might pretend to want to serve Stahlmast to get the upper hand on him. That kind of twist is perfect for an intrigue adventure, so have fun with it!

Roleplaying Stahlmast

Stahlmast is a boastful, narcissistic inventor who has never been able to accept or admit his faults. This pride, coupled with a penchant for hazardous and immoral testing of his imperfect designs, has consistently hindered his success, pushed others away, seen him exiled from Hupperdook, and ruined his once-respected reputation. Driven by blind vengeance, Stahlmast has become the self-styled leader of his personal army of minions, determined to punish all those who cast him aside.

Ideal: “These stupid people didn’t understand my genius, so I will show them. They will regret their ignorance as I prove my superiority… right before I crush them.”

Bond: “My designs, my work—they are a part of me and my legacy. I will do whatever it takes to see my ideas realized in front of those who mocked me.”

Flaw: “I am easily goaded into anger if my plans are ever called into question. I must show others precisely why I am better than them before I can dispose of them. People say that I’m a coward when not fighting from behind my constructs—but they’re wrong!”

If the characters turn down Stahlmast’s offer or if they attack him, read:

The metal plates and spinning gears of the construct churn to life with a grinding noise and a shower of sparks. Stahlmast chuckles. “Though my latest design isn’t fully completed, this trial run shall prove amusing. Thank you for your aid in the testing of my Stahlmaster!”

The Stahlmaster (see the stat block below) surges toward the characters and attacks in a final confrontation. If the Stahlmaster drops to 0 hit points, Huron Stahlmast is ejected from the broken clockwork suit and lands prone in an unoccupied space within 5 feet of it. On his next turn, he attempts to move to the secret door, use his action to unlock it, and flee down the passage to the Underdark (area L20). The door locks automatically behind him, and Stahlmast collapses the tunnel 1 round later to prevent anyone from following him.

Forge

During the fight, any creature pushed into the open forge for the first time on a turn or starts its turn there takes 7 (2d6) fire damage.

Steam Trap Lever

A steel lever topped with a brass sphere is mounted on the east wall. If the lever is pulled, the doors to area L12 close and the steam trap in that area triggers. If the wall holes in area L12 are plugged when the lever is pulled, a jet of scalding hot steam erupts from the forge in a line that is 15 feet long and 1 foot wide, and which deals 10 (4d4) fire damage to each creature in its area (including the Stahlmaster while it remains in its initial position).

Secret Door

The secret door leading to area L20 can be spotted by any character with a passive Wisdom (Perception) score of 13 or higher, or by one who searches the wall and succeeds on a DC 13 Wisdom (Perception) check. The door is locked, and Stahlmast and the drow ambassador from area L9 carry keys that open it. The locked door can also be opened with a successful DC 15 Dexterity check using thieves' tools.

Chimney

A 3-foot-wide iron chimney rises above the forge, eventually leading outside the mountain. See “Ascending the Mountain” for more information.

Treasure

If Stahlmast is killed or subdued, the characters can claim his goggles of night. Any investigation of the Stahlmaster shows that it is beyond repair. However, with one hour’s work, the characters can strip 350 gp of gold and silver clockwork components from it.

L20. Passage to the Underdark

If the characters get access to this tunnel without Stahlmast collapsing the ceiling to cover his escape, read:

A dark, cool tunnel twists down into the mountain, the air growing ever more stagnant. Glowing fungus begins to appear on the walls, which glisten with moisture.

Any character who succeeds on a DC 12 Intelligence (History) check understands that this passage is descending into the Underdark—and knows how incredibly dangerous that subterranean realm is. You might have ideas for other adventures that could lead the characters into the depths, but the players should understand that a successful expedition would require research and resources. For now, the characters are better off heading back and finishing their business in Stahlmast’s lair and in Hupperdook.

Concluding the Adventure

If Stahlmast was killed or subdued, the characters can drag him back to Hupperdook as their prisoner. Turning him over to Watchmaster Bram Gulchswattle with proof of his wrongdoings completes their assignment, and the characters receive the bounty promised them. If Stahlmast got away, the watchmaster pays them 500 gp for thwarting the mad inventor’s dark plots.

If the characters recovered the plans to destroy Hupperdook found in area L5, Bram rewards them an additional 300 gp. If they recovered the letter confirming Stahlmast’s relationship with the Kryn Dynasty in area L18, Bram gives them an additional 150 gp.

New Lodgings?

If the characters made a positive impression on Bram, they might try to convince him to allow them to keep Stahlmast’s lair for themselves once it’s cleared out. Bram agrees to the deal, signing over the location to the party’s care. The characters are now able to clear out the remainder of the lair and turn it into a new—and perhaps somewhat dangerous—home base for their further adventures.

Character Advancement

At the end of this adventure, the characters reach 3rd level. You might have more adventures in mind for Western Wynandir—especially if the characters are able to claim Stahlmast’s lair. But from this point, the course of your campaign is up to you.