In the book, Baró aims to provide the reader with information on St. Madeleine Sophie Barat (1779-1865), the creation and consolidation of the Society of the Sacred Heart, and other historical figures such as St. Rose Philippine Duchesne, who lived as a missionary in the United States, and Anne du Rousier, who took the teachings of the Sacred Heart to Latin America (Panama, Chile and Argentina).

Throughout the book, the author uses texts written by the main characters to provide context for the events that take place so the reader has a clear view of the facts. The missionary vocation of the religious order is also discussed and special attention is paid to the descriptions of the native peoples Duchesne and her companions made contact with.