Puzzle Dungeon: The Seers Sanctum
Table of contents
Credits
ROLEPLAYING ADVENTURE FOR CHARACTER LEVELS 1 THROUGH 3
Requires Old-School Essentials to play.
© 2020, 2026 Directsun Games
Version 3.2
Written by directsun
Cover art by Jacob Fleming
Interior art by Munkao
Floating eyeball art by Alec Sorensen
Layout by Jesse Winter
Map by Old School Jelly
Line and copy editing by Yossi Krausz
Playtesters: CowardlyB, Justin Hamilton, Nick McClure, Laura Boucher, Lydia Snapp
Old-School Essentials is a trademark of Necrotic Gnome. The trademark and Old-School Essentials logo are used with permission of Necrotic Gnome, under license.
Inspirational works: Sufficiently Advanced Magic by Andrew Rowe, Tears of the Crocodile God by Will Doyle, The Legend of Zelda: Ocarina of Time, d100 minor magical items by Goblin Punch
More resources and downloads available at PuzzleDungeon.com
Overview
Hook
A wealthy patron is convinced that before the The Seers disappeared, they learned the secret of interplanar travel. Discover their method and the reward will be more than worth the risk.
Entrance
In an abandoned monastery, a statue of a giant eye hides stairs that lead down to the Fetid Fountain (1).
Dungeon Features
Unless otherwise noted, dungeon areas are unlit. Doors are made of iron and have no handles or hinges. They are meant to slide up into the ceiling when the proper lever in Pool (2) is flipped.
Map
Keys
1. Fetid Fountain
A slick sheen covers the floors and walls. It is the lightly-acidic excretions of the Gray Ooze hiding in the fountain.
A fetid 7’ diameter fountain adorned with eyeless cherubs stands at the room’s center, its basin filled with stagnant, scum-laced water. The surface is murky, but the silver gleam of a sterling hand mirror (200 gp) shines through. The Gray Ooze lurks nearby.
Seated on the edge of the fountain is a lifelike statue of a maiden frozen in an expression of dread. Her right hand clutches the air above the water. She appears to be gazing at the iron door to the south.
The gears that control the iron door of this room are broken. The door slides up with great effort from at least 2 party members. Unless propped open, the iron door will fall shut on its own.
Gray Ooze
Acidic amorphous blob that hides in plain sight.
AC 8 [11], HD 3* (13hp), Att 1 × touch (2d8), THAC0 17 [+2], MV 10’ (3’), ML 12
- Acid: Sticks to struck targets, automatically dealing 2d8 damage per round. Instantly dissolves non-magical armor.
2. Pool
The middle of the room is a scum-filled pool. It runs from wall to wall, with its liquid resting just a foot below the rim. The water is 50’ feet deep and too cloudy to see through.
On the south side of the pool, a pair of 3’ toggle levers jut from the floor, set opposite one another—one pointing north, the other south. Flipping the lever that’s pointed north opens or closes all the iron doors in this chamber except the damaged door to Fetid Fountain (1). Flipping the lever that’s pointed south drains the pool over 10 minutes; flipping it again refills the pool in the same amount of time.
A Jelly Cube is jammed within the mechanism that controls the pool’s water level. When the pool is emptied and refilled, the jelly is forced through the pipes that feed the chamber and reforms to its natural 10-foot cube shape, a Jaunt Lens suspended within its transparent mass. Its bulk displaces the water enough to make the pool overflow by about an inch.
Jaunt Lens
4” loop of bronze around glass.
Reveals objects and passages that don’t normally exist when observed, such as the secret passage to the Treasure Room (5) or the scroll tube in Monkey See (7).
Jelly Cube
10’ block of nearly invisible ooze that slowly digests anything.
AC 8 [11], HD 4* (18hp), Att 1 × touch, (2d4 + paralysis), THAC0 16 [+3], MV 60’ (20’), ML 12
- Paralysis: Save or be paralyzed for 2d4 turns.
3. Petrification Pit
Chains with shackles and 7 gold-plated spears (20 gp each) hang from the walls of the room.
Green light shines from inside a 4’ wall of stones circling a pit. The pit descends 80’ before opening into a room below (9). Its crumbling stonework makes it treacherous to climb. 30’ down, a stone figurehead of The Medusa (10) juts from the south wall, its glowing green eyes fixed northward. Any flesh that falls under its gaze must save versus paralysis or turn to stone.
Beneath the statue’s head, a silver coffer engraved with coiling serpents (200 gp) rests in outstretched hands. Inside lies a Jaunt Lens. If severed from the wall, the head’s petrifying magic continues to function for a month.
4. Transformation Chamber
Tattered leather straps with rusted buckles are attached to a large oak table littered with scalpels and serrated spoons. A crumpled hooded cultist cloak, all black, lies in a heap in the dust under the table.
Faded carvings cover the walls and ceiling. They depict scenes of cultists having their eyes plucked out and placed in jars. The eyes swell in size to that of a small child.
Above the west door, a stone relief of a Goat-Headed Demon with a greataxe crouches over the lintel. Anyone examining the carvings will notice it and see the demon gain color and life, breaking free of the wall and dropping to the floor to block the exit. The demon attacks anyone that can see it. When unseen, it vanishes, returning to its stone perch above the doorway.
On the east wall, a carving of a blindfolded lion hangs above an archway that is solid stone where the opening should be. A hidden passage lies beyond, leading to Treasure Room (5). The wall remains solid while any creature looks at it, but when unobserved, it can be passed through as if it weren’t there.
12 stoppered clay jars, each 3’ wide, litter the rest of the room. Each jar holds a stillborn Floating Eyeball (5).
Goat-Headed Demon
Cursed guardian with cold, sideways-slit eyes and a bleat that crawls up your spine.
AC 5 [14], HD 4+1 (19hp), AT 1 × Axe of Rending (1d8 + rend), THAC0 15 [+4], MV 90’ (30’), M 12
- Rend: Successful attack rolls of 20 or higher reduce the target’s armor by 1.
- Cursed: Doomed to return to its carving above the lintel when unobserved.
Axe of Rending
Successful attack rolls of 20 or higher reduce the target’s armor by 1.
5. Treasure Room
Piles of coins and jewels spill across the floor. Between them drift 4 Floating Eyeballs, 3’ in diameter. Sinuous tendrils trail behind each as they glide silently through the air. In sum, the piles of treasure hold:
- 10,000 cp, 20,000 sp, 3,000 gp
- 20 emeralds (50 gp each)
- Staff topped with a cat’s eye—the wielder sees through the eye as if it were their own.
- Golden monkey idol with its hands covering its eyes—any creature touching it is blinded while contact is maintained.
The eyeballs guard the hoard from any who are not cultists. They float through the chamber, watching intruders with an unblinking stare, often hovering just over their shoulders. They attack only when threatened. During combat (or when non-cultists attempt to leave the room with treasure), one eyeball always fixes its gaze on the exit, sealing the room (attack rolls –4, AC –2 while watching). The eyeballs are conditioned to allow creatures resembling their cultist masters to leave with treasure. Simple disguises, soot-marked eyelids, or a well-timed “Hey, what’s that over there!?” are often enough to fool them.
Floating Eyeball
3’ diameter eyeballs with lids and trailing sinew. Unbeatable at staring contests.
AC 5 [14], HD 3* (14hp), Att 1 × eye ray or 1 x strangle (1d6), THAC0 17 [+2], MV 90’ (30’), M 12
Eye ray: Save versus wands or suffer effects that vary with pupil color.
Pupil color Ability Effect Blue Ray of slow Movement and attacks are halved for 10 minutes. Green Petrification ray Turned to stone. Purple Charm ray Convinced the eyeball is your trusted friend. Yellow Sickness ray Spend the round retching. When finished, save versus poison or the sickness continues.
6. Blind Faith
Anyone who gazes into the room hears squeaky hinges and a loud slam as the enchanted chest closes. When no one is looking, the hinges whine again as the chest opens.
A stone statue stands, blindfolded with a soiled cloth, its gaze fixed upon an oak chest on the floor. The indestructible chest is carved with scores of humans shielding their eyes. When observed, it snaps shut with lightning speed, sundering non-magic obstructions in its path. The chest opens only when no one is looking—including the statue if its blindfold is removed and its eyes meet the chest. Inside, dozens of fat, slimy grubs writhe atop a serpentine silver key (100 gp) to The Medusa’s Lair (10).
Scratches mark the floor beside the statue revealing where it has been dragged aside to access the secret passage behind it—a cramped stairway leading down to Purgatory’s Foyer (9).
5 black, hooded cultist cloaks hang from the walls.
7. Monkey See
A monkey statue gazes down at an empty silver offering plate (50gp) in its palms. A scroll tube hovers above the plate, tangible only when unobserved. The moment any eyes—creature or statue—fall upon it, the tube vanishes, reappearing in place when no one is looking.
Inside the scroll tube rests a Planar Tapestry, which can be viewed normally once removed. The tapestry depicts a lifelike scene from another plane of existence—it might be the River of Souls, a brass city adrift on a sea of fire, or a castle against a gray forest backdrop. This can be any location you wish to send the party to upon solving the puzzle of the Navigation Room (8).
8. Navigation Room
A round table hosts a clutter of cartography. At the table’s center is a wheel marked with runes of different colors. Empty tapestry frames hang on the walls. Scattered sheets of parchment on the table describe impossible worlds, with continents formed from spiraling gas and floating mountains of glass and flame.
The wheel’s central hub is fixed to a spindle, allowing it to turn freely. Atop the spindle rests a 4” bronze loop that holds a shattered glass lens. The device cannot function as a teleporter without an intact Jaunt Lens. Each rotation of the wheel aligns any attached Jaunt Lens with one of the wall frames. Those looking at a Planar Tapestry through an intact lens are instantly teleported to the location depicted within.
9. Purgatory’s Foyer
A circular hole in the ceiling glows faintly green. Scattered across the chamber are shattered stone limbs—hands, legs, and splintered heads—each eerily lifelike. These remains are all that’s left of the victims of the Petrification Pit (3).
The locked iron door to the east is decorated with entwined serpents.
10. Medusa’s Lair
Braziers burn with green flame, casting shifting shadows across statues of armored warriors frozen mid-cower or recoil. Stepped landings are strewn with silk pillows, couches, and enormous shed snakeskins. Ornate columns rise overhead, carved with scenes of serpentine worship.
The Medusa dwells here. 1-in-4 chance she is asleep when the party arrives. When she learns her prison door has opened, she prioritizes escape over anything else.
The Medusa
Bow-wielding half-snake legend with snakes for hair.
AC 8 [11], HD 4** (18hp), Att 1 × snake bites (1d6 + venom) or 1 x arrow (1d6), THAC0 16 [+3], MV 90’ (30’), ML 8
- Petrification: Those looking at The Medusa must save or be turned to stone.
- Averting eyes: Attack rolls –4, AC –2.
- Mirrors: The Medusa’s reflection does not cause paralysis.
- Venom: Save versus death when bitten.