The origins of the House of Mystery are unknown, but it appears to usually exist simultaneously in both the realm known as The Dreaming and on Earth, next to a graveyard (the House of Secrets stands opposite it). The House appears to be sentient, and to act as a repository for stories, normally quite horrific ones. For countless years, Cain, the first murderer, has acted as caretaker of the House, as his brother Abel does the House of Secrets. For a brief period a few years ago, Cain went missing and the House appointed Elvira to be its new caretaker until he returned; the House appears to need a caretaker, even though it is quite capable of looking after itself, and indeed of completely restructuring itself at will. More recently, the House has disappeared from its customary location(s), and become a coaching inn at an extra-dimensional location; Cain spent several months looking for it.