Ravenloft: Strahd's Possession v1.2a (GOG)

The game is based on the Ravenloft campaign setting for the Dungeons & Dragons fantasy role-playing game. The game is set in the domain of Barovia.

The player characters are servants of the Lord Dhelt, leader of the land of Elturel. After an assassin assaults the Lord and steals his Holy Symbol of Helm, the PCs are sent in pursuit of the thief. Instead of catching the criminals, however, they somehow manage to transport the entire party to the mist-shrouded land of Barovia, ruled over by the vampire Count, Strahd von Zarovich.

As Barovia is surrounded by an impenetrable poison mist, the PCs have no choice but to explore the dark land of Barovia, which is crawling with undead and many more nasty things. Strahd, himself, seems interested in the characters' quest for the stolen amulet and invites the party to his castle. The characters' quest is to survive this hostile land long enough to unravel the mystery of the stolen amulet and somehow arrange safe passage out of Barovia