How does the setting create the mood?

The story begins at dusk on a crisp fall day in the 19th Century. The narrator arrives at what he sees as a forbidding mansion in a forlorn countryside. The mansion is covered by a fungus and encircled by a small lake (something like a moat). It is necessary to cross a bridge in order to gain access to the manor. This setting..... dark, forlorn, and broken sets the story's mood.