This is an achievement for Bard's Tale III: Thief of Fate.
In the ruins of Skara Brae, head to the old Mad God's Temple (which is the only one still standing) and give them TARJAN as the name to get access into the catacombs. There's a new exit from the catacombs, directly east of the entrance, which you can get to with a Phase Door or just a walk up and around.
Once you come out through that new exit, you'll be in a small square with a single house that can be entered. Go inside and search multiple times until there's nothing more to be found.