“Gripping…providing new insights into a misunderstood and tragic figure.”—Washington Times After the execution of L ouis XVI and Marie Antoinette, their young daughter, Marie-Thérèse, remained imprisoned. Released on her seventeenth birthday, she faced an uncertain future. Rumor spread that the traumatized princess had switched places with an illegitimate half sister, to live out her days as the mysterious “Dark Countess.” Now, two hundred years later, Susan Nagel finally solves this mystery, creating a brilliant new biography of a remarkable woman who both defined and shaped an era.