Just like her sister, Sisi, Zsófia Mária was born as a Bavarian princess and later became queen, but she - unfortunately - got the throne of Naples, from which the creators of a unified Italy soon removed her. Although Mária Zsófia defends the fortress of Gaeta with bravery that puts men to shame, the overwhelming force prevails, and the royal couple is forced to flee to Rome, to the Pope. When the Risorgimento threatens the papal state, Emmanuel de Lavaysse, scion of an old but impoverished noble family, arrives in Rome as one of the volunteers who want to protect the Holy Father and becomes a soldier of the papal zouave regiment. The accidental meeting of the exiled Queen of Naples and Lavaysse, who takes up arms in defense of the church, sparks love, and from that a child is born, who, however, being an illegitimate offspring, has to hide his origin all his life...

In her book, Lorraine Kaltenbach, a French writer who is distantly related to her heroines, narrates the adventurous life of two women with special fates, a mother and a daughter. After three years of research, the author wrote down the story of Zsófia Mária, whom Marcel Proust called the "soldier queen", and her hidden daughter, Daisy, born from an adulterous relationship.