The Sanctum of Water is a lovecraftian dungeon which requires the party to reason about water levels and vertical space. It uses both top-down and profile-view dungeon maps.

The lovecraftian 'skin' can be easily switched out, and monsters can be replaced/buffed/weakened as appropriate. The underlying puzzle-dungeon structure is best solved by a party without access to magic that would make most of these problems trivial (fly spells, etc.)

I did my best to remove D&D specific stats. Clearly you may adapt it to your system of choice, in whole or in part.

Can be run in a single play session.


(pretty close to the original text in Lovecraft's The Temple)

The ocean floor ahead falls away in a marked declivity, and bears curiously regular blocks of stone in certain places, disposed as if in accordance with definite patterns. You see an extended and elaborate array of ruined edifices; all of magnificent though unclassified architecture, and in various stages of preservation. Most appear to be of marble, gleaming whitely in the rays of your light, and the general plan is of a large city at the bottom of a narrow valley, with numerous isolated temples and villas on the steep slopes above. Roofs are fallen and columns are broken, but there still remains an air of immemorially ancient splendor which nothing could efface.

You examine the scene more closely, and beheld the remains of stone and marble bridges and sea-walls, and terraces and embankments once verdant and beautiful. At the end of the city, facing a cliff wall, you are confronted by the richly ornate and perfectly preserved facade of a great building, evidently a temple, hollowed from the solid rock. Of the original workmanship of this titanic thing you can only make conjectures. The facade, of immense magnitude, apparently covers a continuous hollow recess; for its windows are many and widely distributed. In the center yawns a great open door, reached by an impressive flight of steps, and surrounded by exquisite carvings in relief. Foremost of all are the great columns and frieze, both decorated with sculptures of inexpressible beauty; obviously portraying idealized pastoral scenes and processions of priests and priestesses bearing strange ceremonial devices in adoration of a radiant god. The art is of the most phenomenal perfection, and imparts an impression of terrible antiquity, as though it were the remotest rather than the immediate ancestor of elven art. You cannot doubt that every detail of this massive product was fashioned from the virgin hillside rock of the cliff wall. It is palpably a part of the valley wall, though how the vast interior was ever excavated you cannot imagine. Perhaps a cavern or series of caverns furnished the nucleus. Neither age nor submersion has corroded the pristine grandeur of this awful temple-for temple indeed it must be-and today after thousands of years it rests untarnished and inviolate in the endless night and silence of an ocean chasm.

Dungeon Rules

  • Stone Walls: The walls are made of strange, heavy clay, which is neigh impenetrable, and which faintly exudes an otherworldly affiliation. They are unaffected by transmutation spells. Surprisingly, damaging a wall causes it to slowly heal over time
  • Sleepless: An otherworldly aura blankets the dungeon, infusing one's head with a thoroughly unnerving sensation. Characters are unable to properly rest, and thus gain no health or spells after doing so
  • Underwater Combat: Remember to look up the rules for underwater motion and combat before starting

Dungeon Map

Locations are keyed by green letters. Neither chamber A nor the final chamber are rendered.

A: Entry Hall

You carefully swim into a massive entry chamber, its dark walls ribbed with columns and bracken of the deep. The walls are thick and heavy, built out of a dark material which has the wetness of clay, but upon closer inspection is as hard as stone. While the stone floor is smooth, the walls and ceiling are covered in bas-reliefs of dark idols. The room is charged with a sort of negative energy, the otherworldly aura plaguing your mind with a thoroughly unnerving sensation. You suspect that sleep in an area like this is both unadvised and futile.

The large hall channels backwards to a semi-circular fountain. A large carving of some cyclopean god towers over the chamber, great stone tentacles flowing from beneath a bulbous head. It is difficult to stare at it for too long, for in doing so, your eyes are captivated by intangible lines and drawn towards insidious horror, the overall effect creating stabbing pain within your heads.

There are several doors which exit the hall, all of them barred. However, in the ceiling is as single shaft, ten feet in diameter, which juts upwards into the black rock. The party can swim up it.

B: Shaft

The dungeon begins with water level LOW, so the party must climb the second half.

You swim upwards slowly, careful to equalize the pressure within your ears every ten feet. At last you surface, but to your dismay, there is still much more shaft to climb. Your magical light casts a deep shadow, but it seems that the top lies within the fringes of your vision.

The wall can be climbed at DC 14 on the small hand holds.

You sputter out of the shaft looking like half-drowned sewer rats. The air is dank and heavy, and seems to have been bottled up within the confines of this subterranean structure for centuries. More carvings and reliefs decorate the walls, and what looks like a single, stone door carved in the shape of a gruesome face appears to be your only exit.

The following hall is empty.

C: Main Chamber

The floating pillar begins at its submerged state.

You step into a rather large, cylindrical chamber, its walls coated with the thick perspiration of the clay-like rock. The air is heavy, and humid, and you can hear the sound of sloshing water below.

A short balcony, perhaps ten feet long, protrudes out over the cylindrical hole, and is mirrored by another balcony thirty feet away from you on the other side. You see another set of balconies far above you, and as you carefully peer over the edge, a second set below at the water's level.

The Door to Room D, from the middle level, is locked. It can be picked provided sufficient skill.

A huge lovecraftian squid-tentacle beast swims within the waters at the base of the chamber. It will use ethereal jaunt (3/day) to escape, and plague the party when they least expect it.

There are four plugs at the base of the chamber, which each require a strength check to remove. Upon their release, the central column floats to the water's surface. The central column has a cavity at each floor level:

  1. A treasure chest containing a mask which bestows dark vision and water breathing to the subject. Also, two healing potions
  2. Releases another monster into the chamber
  3. Fully raising the water level allows entrance into the final chamber

D: Floaties

The room beyond is narrow and high, its ceiling reaching up to join with the next level. On the ground are several white stone platforms, resting on iron chains curled beneath them. A long, rusted metal shaft extends up into the air to the next level, its only contents a single white sphere of the same stone which the platforms are made of. Its purpose is unknown.

If the water level is LOW, the floating platforms and the sphere sit on the floor, and the door to room F is locked.

If the water level is MEDIUM or HIGH, the platforms and the sphere float to the top. If the sphere is at the top of its rusted shaft the door to room F unlocks.

Climbing the metal cage requires a DC 12 climb check, after which a DC 18 jump check is required to get to either lip.

The door to room C is unlocked from this side, but is one-way.

E: Mid Water Gate

This strange chamber has four sides, each bearing a large stone face. These are crude, ugly, and exude a demonic mean-spiritedness. Before each face is a shallow trench, which all meet at the chamber center at a rusted metal grate. The door you entered in is similarly fashioned as a face, and you feel watched from all sides.

One can release the water by pulling the jaws of the idols down, or stop the flow of water by pushing the jaws up. All must be opened to start the flow, and all must be closed to stop it. Opening or closing a jaw requires a negligible strength check.

The metal grate can be bashed in with some difficulty or lifted at significantly less dificulty. The shaft below falls into into chamber F.

F: Locked

An octagonal chamber containing four cylindrical metal cages, each with a white stone sphere, arranged in a square. The center of the room contains a circular engraving of the same creature as that of the eldritch statue at the temple entrance. A door is set in the far wall.

Three lovecraftian octopus-melee-monsters sit within the room. In addition, a fourth with spellcasting abilities casts spells as a sorcerer. Spells such as darkness, fear, feeblemind and confusion are recommended.

The door to room G is locked as long as the water level is MED or HIGH.

G: Going Vertical

A circular pool roils in its stone basin. Beyond it are three square indentations, revealing three underlying channels of swiftly-flowing water. A square black block sits on the floor, and above you extends a long shaft.

Pushing a block into a channel increases the water pressure to the geyser, causing its height to increase. Characters can ride the swell up. (Ok, maybe not 100% physically accurate but it works in video games and makes players and myself happy).

All three blocks are required to get the geyser to full height.

The first block is enough to get to the first landing with a jump check. The first landing contains two spell-casting lovecraftian beasts, which launch spells at you from above. It also contains an obvious second block.

The third block is found by searching for the secret shaft from the landing, and following it to the block which seamlessly fits in the primary shaft wall.

H: Pincer Attack

This chamber, when the water level is LOW or MED, requires climbing down the 5x5 shaft into a 5x5 corridor. Note that 5x5 is not enough room to human-sized characters to fight in.

The tunnel contains two gelatinous cubes, one on each end. They slowly close in on the party, forcing combat, a quick tactical retreat, or a nearly impossible climb up the slick walls up the middle vertical shaft.

When the water level is HIGH the gelatinous cubes can swim around. On the plus side, the central shaft can be reached by swimming followed by a slightly easier climb. The chest contains some nice boon. Perhaps a religious idol, a tome of knowledge, or a Circlet of Cerberus.

I: Painful Progress

A perception check reveals that the stone archway over the spike pit is cracked.

Loading the arch with the weight of a human will cause it to fail, and those on it will fall into the spike pit below. There is probably a horrible monster at the base too.

Some methods for safe crossing include tumble checks or by casting reduce size.

When the water level is HIGH one can simply swim.

J: High Water Gate

This is the same as the medium water gate, but activating both can raise the water surface to HIGH.

This strange chamber has four sides, each bearing a large stone face. These are crude, ugly, and exude a demonic mean-spiritedness. Before each face is a shallow trench, which all meet at the chamber center at a rusted metal grate. The door you entered in is similarly fashioned as a face, and you feel watched from all sides.

One can release the water by pulling the jaws of the idols down, or stop the flow of water by pushing the jaws up. All must be opened to start the flow, and all must be closed to stop it. Opening or closing a jaw requires a negligible strength check.

Lifting the grate in this chamber releases a lovecraftian monster, and perhaps some water-logged treasure and adventurer remains.

K: Simple Chest

A stone chest, fixed to the floor, sits behind a vertical metal cage containing a white stone sphere.

The chest is made of the same material as the dungeon. It is locked unless the sphere is pressed against the top of the metal cage, which happens naturally when it floats up at MED or HIGH water levels. Of course, when this occurs the room is submerged.

The chest is trapped with a paralysis toxin but contains a valuable for your troubles.

L: Final Chamber

The final chamber contains whatever you want. A big boss fight? More dungeon? Whatever it is, it requires swimming down into the murky depths to find out...

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