Milady brings the Cardinal information regarding the notorious affair between Anne of Austria, the Queen of France, and the English George Villiers, 1st Duke of Buckingham.

Outside their window, the Queen's seamstress, Constance Bonacieux, stands watching the conversation between the two characters, when she is attacked by the Comte de Rochefort, one of the Cardinal's loyal men.

With the help of his companions, three of the finest musketeers in France, Athos, Porthos and Aramis, D'Artagnan begin their journey to England, and hope to seek the Duke himself, so that they recover the diamonds and restore the Queen's honour.

Though she believes herself safe at a convent in Béthune, Constance receives a visit from her supposed benefactor, Milady de Winter, who poisons her; D'Artagnan arrives at the scene and she dies in his arms.

She is captured and sentenced to die for her crimes, and her magical powers are depleted; Milady is then revealed to be Athos' own wife and that the executioner had once branded her with the Fleur-de-lis symbol.