The Souring of Harrow Vale

investigation and containment

The Souring of Harrow Vale

Lvl Low to mid level, or any equivalent for a starting to experienced party.2 to 5 charactersSingle-session adventure of 4 to 6 hours, or 2 shorter sessions if the party explores every lead.· Moderate to hard. Best for parties that enjoy investigation, tense travel, and one decisive confrontation.

“In Harrow Vale, the river is sick, the bells are ringing, and someone is turning a flood into a weapon.”

— Hook · investigation and containment

QuestgiverMara Vell

Investigation and containment

System-agnostic tabletop RPG adventure

Moderate to hard. Best for parties that enjoy investigation, tense travel, and one decisive confrontation.

Lvl Low to mid level, or any equivalent for a starting to experienced party.

2 to 5 characters

Single-session adventure of 4 to 6 hours, or 2 shorter sessions if the party explores every lead.

4 NPCs

3 encounters

The Opening

“The river in Harrow Vale has turned sour, the fish are dying, and three villagers have vanished near the old floodgates. Tonight, a bell is ringing from a chapel that should have flooded out years ago. Find out what is hiding in the water before the whole vale drinks the lie.”
— Hook · investigation and containment

Set the Scene

Mara Vell meets the party beside a ditch full of dead trout and offers a mug of bitter tea that smells faintly of iron. She explains that the river is changing by the hour, and that a frightened washerwoman has gone missing after seeing lanterns near the old floodgates. Before she can say more, a bell tolls once from the drowned chapel on the hill, though no one in town has rung it for years.

Patron

Questgiver

Mara Vell

Direct but worried. Mara Vell speaks plainly, offers practical help, and avoids accusing anyone by name until evidence is clear.

On the Streets · In the Books

Rumours

d4 · table

01
Old bells ring when the river is about to take a body.
02
The black water avoids iron but eats painted wood.
03
Someone has been paying night-watchmen in fresh coin and damp wool.
04
The chapel vault has a second door below the altar, though no one alive admits to seeing it.

Stakes

If the party fails, the lower Harrow Vale suffers poisoned water, agricultural loss, and a political crackdown that blames outsiders or scapegoats the poor.

Ticking Clock·At sundown, the next sluice release will send the contaminated water downstream to the lower farms and market wells.

Background Lore

Harrow Vale is a rain-soaked border region of old stone mills, black-pine ridges, and drowned chapels. Decades ago, a flood broke the vale's riverworks and scattered the local baronies, leaving behind half-ruined causeways, old burial roads, and a network of smugglers who learned to move through the marsh when the roads failed. Recently, the vale has been plagued by missing livestock, lanterns seen moving in the fog, and a slow souring of the river that has begun to affect crops downstream.

What the World Knows

The river through Harrow Vale has gone sour, and local folk fear the old floodworks are waking up. A worried miller asks the party to trace the source of the contamination, find the missing witness, and shut down whatever is stirring beneath the chapel ruins before the whole valley is endangered.