The Abandoned House in Markarth is a seemingly uninhabited and empty home which the Vigilants of Stendarr believe is being used for Daedra worship. A Vigilant will be asking passers-by for their assistance in investigating the house.
There are numerous chests and containers, an unowned bed that confers the well-rested bonus, as well as services available close by at the entrance to Markarth. It appears that the chests and dressers inside the house do not re-spawn items, and can be used for storage. On the bottom floor, a cave can be found, leading to a shrine of Molag Bal.
On the outside of the house, there is a Shadowmark that indicates that the house is empty.