The story opens with Madame Valmonde visiting Desiree and her baby. On her way to L’Abri, she reminisces about Desiree’s childhood. Desiree was a foundling discovered by Monsieur Valmonde. He found her "lying in the shadow of the big stone pillar," as he was galloping through the gateway to Valmonde. The general opinion was that she was left behind by a "party of Texans," but Madame Valmonde believed Desiree was sent to her by God as she was not able to have her own children.
Eighteen years later, Armand Aubigny all of a sudden falls in love with Desiree when he sees her standing against the stone pillar, even though they knew each other since they were small children, ever since Armand and his father came from Paris, after his mother died. Monsieur Valmonde proposes that before their relationship becomes more serious, Desiree’s origin should be examined. However, Armand is so in love that he does not care about Desiree’s ancestors and decides it does not matter that she does not have a family name of her own, if he can give her a perfectly good one, and so they get married.
Madame Valmonde has a surprise awaiting her. She has not seen the baby for a month and when she arrives to L’Abri she is shocked to see the baby's appearance. Desiree remarks about how much he has grown. However, it is apparent that she does not see anything wrong with her son. She is very happy. Ever since the baby was born, her husband Armand, who was very strict and harsh, has softened a great deal.
When the baby is three months old, the situation in the house changes. Desiree senses there is something wrong. On top of that, Armand becomes cold and avoids both Desiree and the baby. One afternoon Desiree is sitting in her room and starts observing her child and a little quadroon boy who was fanning it. The similarity between them frightens her and she sends the boy away.
When Armand arrives back home, Desiree asks him about the baby. He responds that indeed the baby is not white, which means that she is not white either. Desiree points out all her physical features that strongly suggest that she is white, but her angry husband tells her she is as white as their mixed-race slaves.
Desperate, Desiree writes to her mother, Madame Valmonde, asking for help. Madame Valmonde tells her to come back home because she still loves her. Afterwards, Desiree asks her husband about his opinion and he sends her away. As a result of that, Desiree takes her baby and leaves the house. However, she does not take the road leading to the Valmonde, but instead she disappears in the bayou.
Several weeks after, Armand sets up a bonfire to get rid of Desiree’s belongings. Among the stuff he decides to throw away, Armand finds several letters. Most of them are "little scribblings" Desiree sent him in the days of their engagement, but he also finds one that is addressed from his mother to his father. In the letter, his mother thanks God for her husband’s love, but she also reveals that she is grateful that her son will never know that his mother "belongs to the race that is cursed by slavery."