Floodgate Sewer Den

In the flood tunnels below the city, claws, rust, and old grudges wait in the dark.

4 roomssewereasy

This small sewer complex has been seized by lizardfolk scavengers who turned the old maintenance chambers into a lair. Their den sits above a clogged service channel where something hungry for metal has also made a home.

The sewer tunnels are damp, narrow, and sour with old waste, algae, and the metallic bite of rust. Torchlight gleams weakly on slick brick and black water, while distant splashes, skittering claws, and low reptilian hisses echo through the pipes.

☠ Threat

The lizardfolk defend their stolen lair with territorial fury, but the deeper danger is the rust monster lurking in the drainworks. It has already chewed through old iron supports and will eventually cause a collapse if it is not driven off or slain.

History

These sewers were built beneath an old riverside quarter to drain floodwater and industrial runoff. When the district was abandoned after repeated collapses, a small lizardfolk band moved in, using the dry service rooms as nesting space and storage. They soon discovered a rust monster in the lower drains and now feed it scraps of metal to keep it from prowling the streets above.

Encounter Table

CR
1/4CR
Lizardfolk Hunterx1

A lone lizardfolk hunter stalking the corridors for intruders or strays from the main lair.

1/2CR
Sewer Scavengerx1d2

A skittish sewer scavenger dragging a sack of scrap and bones, desperate to flee rather than fight.

1/2CR
Young Rust Monsterx1

A small, hungry rust monster sniffing for iron fittings and unattended weapons.

Rumours & Whispers

1

The sewers are haunted by lizardfolk that wear watch badges as trophies.

2

Something in the drains can eat iron fast enough to ruin a sword in seconds.

3

A city worker vanished near the floodgate, but his lantern was found neatly stacked in a dry chamber.

4

There is a hidden vault below the sewer where the old district's emergency supplies were stored.

Quest Hooks

1
The Gate Is Failingcleanup

Quest giver: Captain Veyra Holt

A city guard asks the party to clear the sewer before the rust monster eats the iron gate that protects the riverside market.

25 gp each and official favor with the city watch

2
Stolen in the Slimerescue

Quest giver: Milo Grent, tannery foreman

A terrified tanner claims the lizardfolk stole a family signet and hid it below the drains.

A silver reward purse and a masterwork tool kit

3
Lantern in the Darkrecovery

Quest giver: Sister Alwen

A shrine keeper wants the party to recover a blessed drain-lantern lost in the sewers before it is melted by corrosion.

Healing potions and a minor blessing

Corridor Notes

Between Room 1 and Room 2

Waist-high runoff channels carry slow gray water, forcing careful footing and leaving slick moss on the walls.

Between Room 1 and Room 3

Bent iron grates in the floor hiss when stepped on, venting warm, foul air from deeper drains.

Near Room 1 and Room 4

Scratched lizardfolk glyphs mark safe ledges, hidden routes, and a warning sign for intruders.

Throughout the dungeon

Rust freckles the brickwork in broad orange stains, and any metal left here too long feels gritty to the touch.

Visual sheet

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