As the heroes track the Cultists of the Whispering Way through the fog-shrouded streets of Caliphas, they lose their quarry -- but a dark patron rises with offers of aid and insights into the cult's ultimate evil. He asks only in return that the adventurers put an end to a murderer terrorizing the city's vampires. This leads the heroes into an underworld of endless night, where they must explore the vampires' deadly society and indulge its blasphemous...