i6: Ravenloft (1983)

From the web:

In Ravenloft, the PCs receive a plea for help from the Burgomaster of Barovia to save his daughter from the the vampire Count Strahd von Zarovich. The PCs must then use all their abilities, innovation and wit merely to stay alive, not to mention destroying the evil vampire. If the DM does his/her best, this can be one of the most thrilling, dangerous, deadly and exciting modules around. Features a two-page color map of Barovia, and some terrific three-dimensional maps of the castle. 32-page booklet with 2 covers. 

From the front cover:

The master of Ravenloft is having guests for dinner - and you are invited. Ravenloft is an adventure for 6 to 8 characters of levels 5 to 7.