In the lobby of the hospital of the City of Mexico, Dr. Alberto Robles receives a letter from his friend Juan the priest of Santa Cruz. In the text, the priest tells him that they both lived before his departure, and the reason why Alberto decided to leave the town where he struggled against gullibility and ignorance of the people towards their science and against David, chieftain who abused his power by invading land, such as a farmer Roque Suazo, who leaves the town after the death of his mother for being staffed by a healer instead of a doctor. Later, Roque returns to fight their land and falls in love with Soledad, a peasant who is in love with Alberto. Soledad pregnant from rape and dies during childbirth, so Alberto decides to go to the city.