​​Everyone sees the house they want to see... Paris, 1900: Amidst the decadence of the Belle Époque, American heiress Lydia Temple falls in love with ethereal aristocrat Séraphine de Valleiry, and builds her a whimsical castle in the Swiss mountains. The Chateau des Miroirs becomes a bastion of spiritualism until it is taken over by sinister forces during the First World War. And then it disappears. Or did it ever really exist? Oxford, 2035: Elderly professor Cyrus Field is rapidly losing his sight and his will to live, when student Haydn Young presents him with a collection of letters previously lost to history. These letters may contain the answer to the philosophical problem that has been his life's work. But does he really want to know the truth? With war closing in, Cyrus and Haydn must decide whether to risk everything in the quest for knowledge. The mystery of the Chateau des Miroirs reverberates through the generations, connecting two souls that are destined to find each other.