Rats in the Walls (Astonishing Swordsmen & Sorcerers of Hyperborea) (2014)

From publisher blurb:

TAKEN from DUNWICH

An adventure in HYPERBOREA designed for 4–6 characters of 1st through 2nd level. For use with Astonishing Swordsmen & Sorcerers of Hyperborea™ and other traditional fantasy role-playing games.

In the City-State of Khromarium, a dockside tavern called the Silvery Eel is plagued by rats of a most unusual breed. These abominable rodents have ruined the tavern keeper’s business and his life. The man is desperate, and he offers a substantial reward for the elimination of his horrific problem.

Note: This adventure was originally presented in Knockspell #4.