Every framework on this site works the same way: it gives you the load-bearing structure of an adventure and nothing more. No named NPCs you’ll never use, no boxed text you’ll skip, no map you have to honor. Just the shape of the thing, the pressure points that make it move, and a set of prompts to fill with your own table’s imagination.
This one is built for a port town and an investigation. A quiet harbor, a prize moving through it, and a group of locals who answer to something older and colder than the harbormaster. Drop it into any nautical campaign, or use it as the reason your party’s ship makes port in the first place. I thought of this framework to be used in a campaign I will be running in the near future as a starting point. The ideas you generate in this adventure could be threads that shape an entire nautical campaign.
The Pieces You Choose
Before you run this, make five decisions. Everything depends on these choices, but don’t overthink them. I’ve generated a few ideas for each to get the thoughts flowing. Pick one, roll, or use them for inspiration for your own idea.
The Port
What’s the town’s name, and what’s its one defining trait? Use these traits to shape every scene.
| d10 | The town and its defining trait |
|---|---|
| 1 | A whaling town thick with the smell of rendered fat and old blood |
| 2 | A glittering free port where every flag is welcome and nothing is asked |
| 3 | A garrison harbor under martial law, papers checked at every corner |
| 4 | A drowning city, half its streets reclaimed by a rising tide |
| 5 | A pilgrim’s port, where the faithful arrive by the boatload for a holy site |
| 6 | A smuggler’s haven pretending very hard to be respectable |
| 7 | A company town owned wholesale by a single trading house |
| 8 | A festival port mid-celebration, drunk and distracted and crowded |
| 9 | A plague-shadowed harbor under quarantine, nerves stretched thin |
| 10 | A frontier port at the edge of the known map, last stop before the deep |
The Deity
The cult serves a sea god. You decide its nature. Keep it simple for and thematic for your world; what matters is what it wants, not its name (for now).
| d10 | The sea god and what it wants |
|---|---|
| 1 | A drowned god of endings — it wants what is owed returned to the deep |
| 2 | A hungry storm-bringer that feeds on fear and offerings of the lost |
| 3 | A patient leviathan that trades in bargains and collects on every one |
| 4 | A god of tides and cycles, restoring something the surface world stole |
| 5 | A many-mouthed thing beneath the waves, always whispering, never full |
| 6 | A cold sovereign of the depths reclaiming a relic of its sunken court |
| 7 | A god of safe harbor turned vengeful, punishing a city that forgot it |
| 8 | A twin-faced deity of calm and wrath, and the calm is the dangerous one |
| 9 | A dead god whose corpse still dreams, and the cult tends those dreams |
| 10 | A rising god, newly awake and assembling the pieces it needs to fully wake |
The Prize
The McGuffin moving through the port. It should be small enough to carry and large enough to matter. The cult needs it. Decide why later, or never.
| d10 | The McGuffin moving through the port |
|---|---|
| 1 | A sealed reliquary that hums when the tide turns |
| 2 | A living prisoner who must not be allowed to speak |
| 3 | A chart to a place that was deliberately erased from every map |
| 4 | A child who doesn’t know what they are |
| 5 | A drowned bell that rings on its own below a certain depth |
| 6 | A cask of water from a sea that no longer exists |
| 7 | A key, plain and iron, that the cult will trade an empire to possess |
| 8 | The preserved heart of something that was never meant to die |
| 9 | A ledger naming everyone the cult has ever turned |
| 10 | A passenger traveling in secret who is also hunting the cell |
The Cell
The local group following the cult’s orders. What’s their cover? The better the cover, the better the adventure.
| d10 | The cell’s cover identity |
|---|---|
| 1 | A stevedores’ union that controls who loads what, and when |
| 2 | An old merchant family with fingers in every warehouse |
| 3 | A temple of a different, entirely respectable god |
| 4 | The harbor pilots’ guild — they board every ship that enters |
| 5 | A charitable order running the dockside almshouse and soup line |
| 6 | The customs house itself, rotten from a few key desks |
| 7 | A troupe of performers who travel port to port without suspicion |
| 8 | A fishing collective whose boats go out at strange hours |
| 9 | The night watch, or enough of it to matter |
| 10 | A respected shipwright’s yard where things are built and hidden |
The Tell
The one detail that defines those that are involved.
| d10 | The detail that can’t be unseen |
|---|---|
| 1 | A shared tattoo, half-hidden beneath a sleeve or collar |
| 2 | A tide-table that’s always wrong by the same precise margin |
| 3 | A hymn hummed by people who claim not to know each other |
| 4 | Salt left on doorsteps in a pattern, swept away by morning |
| 5 | The same knot tied in unlikely places — fences, rigging, hair |
| 6 | A word used as a greeting that means nothing in any local tongue |
| 7 | Eyes that flick to the water before any important answer |
| 8 | A particular fish never sold at market, always bought in quantity |
| 9 | Doors and shutters that face the harbor, never the street |
| 10 | A limp, a scar, or a milky eye shared by too many to be chance |
The Secret
This section is for the Game Master.
The cell has spent months embedding itself in the port’s dock system — not to run it, but to understand and infiltrate it. They know which berth a ship takes, which inspector waves which cargo through, and when the night watch thins. They’ve been told the Prize is coming. They don’t know exactly when, and neither do their masters; that uncertainty is the engine of the whole adventure. When it arrives, they have a narrow window to take it before it moves on.
The players don’t begin knowing any of this. They begin noticing that something about this port is off. The framework’s job is to turn noticing into knowing, and knowing into an adventure.
The Shape of It
Think of the adventure in four pressures, not four acts. Each one raises the stakes and narrows the time. The players can move through them in almost any order — what matters is that the pressure keeps building. Each of these should build toward the eventual climax of the adventure.
Pressure One — The Ordinary Port. Establish normal before you break it. Give the party a reason to be here that has nothing to do with the plot: resupply, a contract, a night of shore leave. Let them meet the town. Seed the Tell here, in the background, unremarked. They shouldn’t catch it yet. That’s fine. You’re loading a proverbial gun you’ll fire later.
Pressure Two — The Snag. Something small goes wrong, and it brushes against the party directly. A dockhand they spoke to yesterday turns up missing. A crate with their name on it is searched by people with no authority to search it. A stranger asks a question they shouldn’t know to ask. This is the inciting brush — whatever idea you have here should be the seed that foreshadows the larger issue. Make this personal to the characters, but not too personal. This should feel like a red herring, but really it is making the plot feel natural.
Pressure Three — The Pull. The actual adventure. The party follows the thread and finds the cell behind it. This is the heart of the adventure and the part you should prep least — it’s where player agency lives. (See Discovery Vectors below.) The goal isn’t a single clue trail; it’s a web, so that whatever the players poke, something pokes back.
Pressure Four — The Window. The Prize arrives, or its arrival becomes imminent, and the cell moves. The investigation becomes a race. The players now know enough to act, and they’re out of time to keep gathering. This is the climax. (See The Window below.)
Discovery Vectors
The single biggest failure mode of an investigation is one clue, one path, one gate the players have to find the key for. Build a web instead. Below are vectors — or ways in — this should not be seen as a sequence of events. Prep three or four. Whichever the players pursue, let it yield something true.
- The Witness. Someone saw something they don’t understand and will talk for the right reason — maybe coin, kindness, or fear. Refer back to the Tell. Make sure to include a piece of defining information here. “The guy was acting weird when I was talking to him. His eyes kept shifting back to the sea as if he was looking for instruction”.
- The Paper Trail. Manifests, berth assignments, inspection logs. Something in the records doesn’t add up: a ship that never sails, a cargo that’s always “still being processed.” Investigation-minded players will dig here. Give the characters something to go off of. This should link directly to the operation. Maybe the ship they are using to transport The Prize has been in the dock for way too long, or the warehouse they are renting hasn’t had any shipments in the last month recorded in the logs. Point them to something to investigate.
- The Tail. The cell is watching the docks, which means the cell can be watched back. A stakeout reveals a meeting, a handoff, a face that appears where it shouldn’t. An idea for this could be a person in the docks that doesn’t belong. A local merchant that “wouldn’t be caught dead in the dock district.”
- The Loose Member. Not everyone in the cell is a true believer. One of them is in over their head — coerced, indebted, or afraid. The party can leverage this person and provide an out for the right information or apply their own pressure.
- The Direct Provocation. Some parties don’t investigate; they kick doors. If they move openly, let the cell react — and reaction is information. Who panics? Who reaches out to whom? Aggression should reveal the network, not dead-end into it. There should be enough cell members in an altercation that one gets away. Let the party follow them. Or they leave behind something in their haste that provides a clue.
The rule: every vector confirms the cult cell exists and is after something. No single vector reveals the whole picture. Three vectors together should be enough for clever players to predict the Window before it opens. Generate truths from each of the vectors that point the characters in the right direction. Think of what will get the party to EXACTLY the moment in time where the event will occur. This should be more than one defining fact - a time, a place, a person, a ship, etc. Each vector should generate just a piece of this.
The Cell
Don’t stat out a roster. Define roles and put names and plot points to only these members. This is not an exhaustive list nor are any of them required. Use the ones that generate inspiration for you and that will be easiest to run at your table.
The Leader. The cell’s leader in the port — competent, careful, and devout. They believe. They are the hardest to turn and the most dangerous to corner. This is the BBG for this adventure.
The Cloaked Figure. The cell’s public face, embedded in the cover identity — the union rep, the merchant, the respectable priest. Charming, plausible, and the last person anyone suspects. Often the one the party likes or has interacted with at some point during the adventure sequence. Seeding this person early on is best.
The Eyes. The watchers and infiltrators inside the dock system. The low-level replaceable folks that are the easiest thread to grab. Most of the party’s early progress comes through the Eyes.
The Tide. The cult’s actual reach — the thing the Leader prays to and occasionally hears back from. Keep this off-screen and ambiguous as long as you can. Is it a distant high priest? A presence in the deep water? Let the players’ dread fill the gap. This could be the connecting tissue that turns this into an entire tier’s (or multiple tier) plot line.
For each role you actually use, decide one want and one fear. That’s enough to improvise them all night.
The Window
The climax turns on timing, so give yourself a clock. A simple six-segment track works: each time the players make meaningful progress, the cell also advances toward the heist. When the clock fills, the Prize arrives and the cell moves — ready or not.
This does two things. It creates immediate stakes (the players can feel the time bleeding away) and it means the climax happens whether or not the players are fully prepared — which is far more exciting than a heist that politely waits for them.
When the Window opens, the cell makes its move on the Prize. The shape of the confrontation depends entirely on what the players did to get here:
- If they stayed hidden, they can set an ambush — but so can the cell, if it caught wind of them.
- If they went loud, the cell accelerates, moving early and sloppy. More chaos, more collateral, a desperate snatch instead of a clean one.
- If they turned a member, they may know the exact when and where — or be walking into a feed of false information.
Resolve it as the situation demands: a chase across the wharves, a standoff on a deck at midnight, a quiet knife in a customs house. You don’t need to script it. You need to know what the cell wants (the Prize, gone before dawn) and let the players try to stop it.
After the Tide Goes Out
However it ends, leave threads in the water:
- The Prize is secured — but the Leader escaped, and the cult does not forgive failure.
- The Prize is taken — and now the party knows where it’s going, and why that’s worse than they feared.
- The cell is broken — but the Cloak was only ever a middle link, and something in the deep water has noticed the people who interfered.
A good port adventure should make the next port feel watched.
The Fill-In Worksheet
Copy this, answer it, and you’re ready to run:
- Port name & defining trait: ______
- The sea deity & what it wants: ______
- The Prize & why it’s moving through here: ______
- The cell’s cover identity: ______
- The Tell (the unmissable-once-seen detail): ______
- Three Discovery Vectors I’ll prep: ______
- The Leader’s want / fear: ______
- The Cloak’s want / fear: ______
- What happens when the Window opens early: ______
That’s the whole framework. Nine answers and a clock, and you have an evening (or a few) of paranoia, salt air, and a town that isn’t what it seems. Make it yours.