The two novels tell the story of Mar a and her widowed father, Enrique Aracil, a physician, from her earliest years, sharing her life with family members and growing into womanhood. Her father's involvement with the anarchist movement brings him in contact with a young fanatic Nilo Brull, who fails in a desperate attempt to assassinate the young king and his bride, throwing a bomb at their open carriage on their wedding day. Aracil is accused of abetting the bomber, and he and his daughter are forced to flee Madrid.
The first novel follows the pair as they travel on foot and later on horseback through the countryside west of the city on their way to Portugal. The author describes in great detail all their adventures as they move from one town to the next, staying at inns and meeting the many characters on their way. It ends with their voyage by sea from Portugal to London.
The second novel describes their stay in London, at a pension in Bloomsbury, and the various people they encounter while they remain in London. Baroja reveals the influence of his favorite author, Charles Dickens, throughout many picturesque scenes.
When they consider it's safe to return to Spain, they sail back, and Marie ends up marrying her cousin.