Violaine, a widow and mother of two, lover of books, finds herself in a proposition. After she discovers that her father sold her to a marquise in Boisaulne, she must leave her son and daughter in order to move in with the marquise. This is where she meets the marquis du Herle, also known as Harlequin, who brings her the the Castle of Enlightenment.
Heartbroken and lonely, Violaine discovers the vast library that holds treasures she never expected. But, Violaine discovers that the chateaux des Boisaulne has much more to offer than she thought.