The Mournmere Survey: A Haunted Lake D&D One Shot for 2-3 Players

The Mournmere Survey is a haunted lake D&D one shot for 2-3 players that drops your table into a drowned valley where the dead were never moved and the water never forgave it. Built for fifth edition and a single evening of play, it trades the usual dungeon-crawl grind for slow-building dread, a failing ring of wards, and a choice no one at the table will make lightly. If you have wanted a horror night that feels less like a fight and more like a ghost story your players have to survive, this is the one to put on the table.

A Quiet Survey That Goes Very Wrong

The party is hired by a cartographers’ guild to do something simple: chart a remote mountain reservoir and map its shoreline. It should be a paid afternoon on still water. Instead they find the abandoned camp of the survey crew who came before them, gear left where it fell, and a ring of weathered standing stones that nobody local will explain.

Forty years ago the valley of Vethryn was flooded to make this reservoir, and the village beneath it was drowned with its dead still in the ground. Someone down there has been grieving ever since. The wards that have kept her bound are failing one by one, and the quiet survey that brought the party to the water is about to become the worst night of their lives. The lake does not move the way water should, and by the time anyone realizes why, the shore is already a long way behind them.

Why a Drowned Lake Makes Such Good Horror

Still water is one of the oldest and most reliable sources of dread, and this adventure leans into all of it. You cannot see the bottom. You do not know how deep it goes. Something that wants you has every advantage the moment you step off dry land, and the surface stays mirror-calm while it takes you. A haunted lake D&D one shot built around that fear does not need jump scares; it just needs the players to understand, slowly, that the safest thing they can do is stay out of the water, and then it takes that option away from them.

The drowned village underneath adds the second layer. This is not a monster that wandered in from the wild. It is the consequence of something people did and then tried to forget, and the reservoir is the lid they put on it. That gives the horror a moral spine, the kind that keeps players talking about the session long after the dice are away.

Horror That Builds on a Clock Your Players Can See

The dread here is structured, not random. Five warding cairns ring the water, and each one that falls wakes the spirit a little more. The players can watch the danger climb in real time, which turns every decision into a gamble: stop to investigate and learn the truth, or push on before another ward gives way. The adventure tells you exactly how the lake escalates as the wards drop, so the Game Master always knows what the night looks like at each stage.

A cinematic drowning mechanic gives the water real teeth without turning it into an instant kill. A character pulled under becomes a heart-pounding rescue the rest of the party can attempt, not a sudden character sheet in the bin. The result is a session that tightens steadily from an uneasy afternoon into a desperate midnight stand on the last patch of dry ground, with the floodline rising the whole time.

A Tragedy, Not Just a Monster

What lurks in the reservoir is not a faceless horror. She was a person, and the adventure never lets the table forget it. As the party uncovers what was buried and who was abandoned to the rising water, the question quietly shifts. It stops being how to kill the thing in the lake and becomes what the dead are actually owed, and who is really to blame for what happened to the valley.

That weight pays off in three distinct endings. The party can lay the spirit to rest, destroy what binds her, or flee the valley and leave it to drown. None of them is the obvious right answer, each costs something different, and the one your table reaches will say as much about the players as it does about the dice. It is the kind of ending that earns a long, quiet pause before anyone reaches for snacks.

Designed for Small Groups and Ready to Run

This is a Ready Adventure Series one-shot, which means it is built from the ground up for 2-3 players at levels 2-3, with scaling notes baked in for a duo or even a one-on-one game. Two players and a Game Master is not an afterthought here; it is the target. Encounters, pacing, and the drowning rules are all tuned so a small table feels the pressure without getting steamrolled.

Everything a Game Master needs to run the night is on the page. Read-aloud boxed text sets each scene, scaling guidance keeps the fights fair for a small group, and clear notes tell you how to run every encounter, what the players can discover, and how to handle the moments that matter most. There is combat in every act, but the real engine of the night is the mystery, the rising water, and the choice at the end. You can open it cold and run it the same evening with no preparation at all.

How the Night Unfolds

Without spoiling the turns, the session moves through four tight acts. It opens on the still water and the eerie remains of the last crew. It builds as the party walks the ring of failing wards and uncovers the drowned village and the truth the guild would rather stayed sunk. It breaks open when the water finally wakes and the dead stop staying where they were put. And it ends at midnight on the last high ground, where the party has to decide what they are willing to do for a stranger who has been dead for forty years. Each act has its own threat and its own discovery, so the table is always learning something new about the valley right up to the final scene.

What’s Included

• A complete four-act horror adventure playable in a single 2-3 hour session
• Tuned for 2-3 players at levels 2-3, with built-in scaling for a party of two
• Nine ready-to-use stat blocks, from the drowned dead to a towering guardian of stone and coffins
• Five battle maps, including a full regional map of the valley so you can see how every location connects
• Four pregenerated characters, each with tactics notes and a personal stake in the story
• A signature cinematic drowning mechanic and a failing-ward doom clock
• Three distinct endings, plus opening hooks, contingency guidance, a full aftermath, and threads to carry the story onward

Perfect For

• Busy Game Masters who want a polished horror session without the prep grind
• Small tables and duets, including two-player and one-on-one games
• A single haunting evening, a convention slot, or a one-shot break from a longer campaign
• Horror fans who prefer atmosphere and tragedy over a straight dungeon crawl
• Spooky-season tables looking for a self-contained scare to drop into any 5e game

Part of the Ready Adventure Series

The Mournmere Survey is part of the Ready Adventure Series from Anvil N Ink, a line of zero-prep one-shots built for small groups and short evenings. The series runs the full tonal range, from comedy and heist to courtroom farce and cosmic dread, and this is its haunted-water horror entry. If your table likes this one, the rest of the line is built on the same promise: open the book and play. Each release is designed to stand completely on its own, so you can pick the night that fits your group and run it without touching anything else.

Run a Night Your Table Won’t Forget

You do not need to prep a thing. You do not need a big group. You need one evening, a small table, and the nerve to take your players down to a lake that should have stayed quiet. The Mournmere Survey gives you a complete, atmospheric, genuinely unsettling 5e horror session in a single sitting, available in paperback and PDF from Anvil N Ink. Set the lights low, read the first box of text, and let the water do the rest.

The Mournmere Survey is a haunted lake D&D one shot where the water remembers every name it took — and the only way out is to answer it.