In Kate Chopin's 'Désirée's Baby,' the story revolves around Désirée, who faces a devastating revelation about her ancestry and her husband's cruel accusations after their child's racial identity becomes a point of contention. As Armand, her husband, turns cold and dismissive, Désirée's anguish leads her to make a tragic decision. The narrative culminates with Armand's realization that he himself is of mixed race, revealing the irony of his prejudice and the consequences of his actions.