The story is set in Paris in the early 20th century. Florian Rochefort, the only son of a destitute aristocratic family, becomes the collateral of Ray Balzac Courland in exchange for a loan the pawnbroker provides to Florian's mother to help pay off some of the family's debts. However, Ray is actually the notorious thief Noir, who, due to his particular fondness for extraordinary jewels, could not resist adding Florian's striking amethyst eyes to his collection. As the narrative progresses, the reader accompanies the protagonists on their adventures across France, Morocco, and Tunisia, witnessing the deepening of their relationship.