A stranger, lost while hunting in the moors of Brittany, meets the mysterious Demoiselle D'Ys. She invites him back to her castle, and the two grow closer. After a while, however, the stranger begins to suspect that the other inhabitants of the castle are not from the world as he knows it. "Demoiselle D'Ys" is a quintessential romantic horror story from Robert Chambers' collection, The King in Yellow.