The Adventure Seed
Red Reign of the Rat King
The players come across a mysterious artifact: a sculpture of a nest of rats with their tails intertwined. The sculpture is an heirloom of an ancient family of vampires and serves as a focus for the vampire's natural (or supernatural) ability to control vermin. In addition, it permits the weilder to transform humans into were-rats under the weilder's domination!
A powerful vampire wants the heirloom back. Can the heroes stop him becoming the Rat King?