House on the Fields

From the introduction:

There is a house nearby that has been empty ever since the entire family- servants, children, and all- vanished. It has lain empty for twenty years, and it is said that all who go near it go mad. Normally, the house maintains its distance. The villagers don’t approach the house, and the house leaves the villagers alone.

However, recently, a darkness has been spreading from the house, and the people are fearful that the curse of the house will infect the village. The house itself if two miles out from the town, but you can see a vague dark shape atop the hill from the center of the village. A party of adventurers must go and explore the house, to try to stop the darkness there.