An adaptation of Fiodor's Dostoievsky novel Crime and Punishment set in the XX Century Mexico. Ramón Bernal is a poor student in Mexico City that has abandoned his career when he receives a letter informing him that his sister will marry a rich man. Thinking she will marry for money instead of love and feeling guilty about this he murders an old usurer to steal her money. With feelings of guilt he gets severely ill while his friend and family don't suspect he got anything to do with the murder, but as the murder investigation moves along inspector Porfirio Marín suspects about the student. Ramón also meets Sonia, a prostitute, and fells in love with her, the girl will teach her about regret and atonement.