"The Demoiselle d'Ys" is Robert W. Chambers' haunting tale of a young American hunter who becomes lost on the Breton moors and stumbles upon a mysterious château inhabited by a beautiful, otherworldly woman. Published in 1895 as part of *The King in Yellow*, this story exemplifies Chambers' mastery of atmospheric supernatural fiction, blending medieval romance with uncanny temporal displacement. The narrative explores themes of love, enchantment, and the thin boundaries between the living world and realms beyond time.