A girl discovers that, behind the woman who looks at her sternly from the dark family portrait, lives a red-haired girl, who runs free through the Cantabrian mountains, along with her Danish dog. She decides to draw to find out who that girl and teenager were that ends up becoming one of the greatest thinkers and writers of the 19th century. Breaking the image that has been given of Concepción Arenal until now is the purpose of this rigorously documented fictional book, imagined by the illustrator Teresa Novoa, great-great-granddaughter of Concepción Arenal, and the writer Mónica Rodríguez.