Mr Janek's House is a major location found in The Village. It can only be accessed by going through The Village Well, where the player will emerge inside the house, from the large hole in the floor.
The house is first mentioned by the Musician, who believes that a spare key to the Pretty Lady's room can be found inside. The house does indeed include said key as well as a Dog Tag and various other randomized bits of loot. It's necessary to retrieve the key in particular to continue with Darkwood's story.