Blackbriars

Blackbriars is a Ravenloft one-shot adventure in two parts for 1-4 characters of roughly level 5. It is set in an ambigous domain of Ravenloft, allowing you to place it wherever you wish, even inserting it as a deadly side-quest for your non-Ravenloft campaign. The adventure invokes themes from the survival horror genre. It can take anywhere between 4-8 hours to complete depending on how much of the material you opt to use, and your group's speed at handling combat encounters.