Sewer Salvage CR3

The local sewer system is managed by a group of kobolds that lives beneath the city. Recently they have complained to the ruler that something down there is attacking them and refuse to do maintenance until the issue is solved. This is obviously causing a headache for the ruler, who enlists the PC's help in resolving the issue.

Although distrustful of outsiders, the Kobolds will tell the PCs that a team had been extending the sewer tunnels to the west when they disappeared. Since then other Kobolds have gone missing from various places in the sewers.

The cause of the disappearances is a large crocodile lair that the Kobolds have recently tunneled into. With its lair now connecting to the sewers it has taken to hunting Kobolds travelling the narrow sewer pathways.

Although the attack can happen anywhere in the sewer network it is assumed that the PCs will strike west. The pathways in this section of the sewers have not yet been widened and subsequently present difficulty for creatures of medium size. A medium creature moving along this narrow path will need a DC 15 acrobatics check to avoid falling into the swiftly flowing sewer waters. Characters with a acrobatic bonus of 5 or higher(Or trained for PF2) may forgo this challenge.

Should a player fall into the water(or be dragged in by the crocodile) they will be swept 10 feet farther west towards the crocodile’s lair each round. Large creatures such as the crocodile can resist this current passively. The rough waters require a DC 15 swim or athletics to navitage.

Statistics for a crocodile in Pathfinder 1e can be found here. Statistics for a crocodile in Pathfinder 2e can be found here.

Additional Notes/Alterations

If you want this to be more combat-heavy without invoking further plot repercussions, it's easy enough to add a few other creatures, such as rats or oozes. To add even more danger, feel free to include occasional flash-floods, requiring the party to seek out higher elevation or other, creative means of dealing with the complication. With the flooding, you could also introduce a time limit; the sewers need to be cleared (perhaps also of an additional obstruction) quickly because a big storm is coming that will severely harm the city if the sewers are inoperable.

If you want to turn this into a plot hook with further-reaching implications, instead of just a one-session quest, there are definitely ways to do that as well. The PCs could find the dead body of a murder victim, with some kind of note leading to the mystery of who killed them and why (or perhaps some further intrigue they were involved in). Sewers are also a fairly traditional location for the headquarters for a thieves guild, or other unsavory types. Being caught unawares in that area could be bad news for PCs who now need to talk their way out of the situation, and who have now made some new contacts along the way. The crocodile's lair also leaves room for some interesting developments; it could be hiding in some old ruins, or the abandoned hideout of some secret group, or even the lair of an older, mysterious creature that seems to have moved on... somewhere.