The resolution of a story takes place after the climax. It is the part of the story where the conflict comes to an end. In Kate Chopin's "Désirée's Baby," the resolution comes after Désirée and her baby leave the plantation.
She disappeared among the reeds and willows that grew thick along the banks of the deep, sluggish bayou; and she did not come back again.
Weeks after her disappearance, Armand orders his slaves to put up a huge fire. In it, he burns all of the things that used to belong to Désirée and the baby. There were also letters thrown in the fire, some from Désirée, and others from Armand's own mother. Chopin ends the story by citing the writing on the letter, in which Armand's mother states that she is very grateful to God for her husband's love. However, she was even more grateful for the fact that Armand will never have to find out that she, his mother, is African American.
This is significant because the entire reason Désirée leaves Armand is because their baby has developed African American physical traits. These were the days before the Civil War, and slavery was in full swing. That the baby was black meant that either Armand or Désirée was also of the same descent. Armand, who is a cruel and difficult man, automatically blames Désirée for it and insists that she is the one who carries this heritage—that it is her fault that their child is of "the race that is cursed with the brand of slavery."
In total despair, Désirée leaves the plantation, presumably to go see her mother. What she does, however, is drown herself and the baby in the bayou.
Therefore, the resolution is tragic and ironic because it is now clear that Armand is the one who carries the African American genes in his blood, from his mother, and he has just caused the unnecessary and cruel deaths of his wife and child.