In late-1980s Richmond, twenty-five-year-old Preston Ashford is preparing to marry Caroline Bancroft when his mother, Eleanor, confesses that after her own newborn died, she secretly exchanged him for the healthy child of a Georgia woman named Farrell. Sworn to secrecy and unable to tell Caroline, Preston retreats into a hotel affair with a call girl known as Simone, until she recognizes the details of his birth, returns his money, and vanishes. He follows her to Merritt, a South Georgia mill town, where she is Darla Jean Farrell, daughter of poultry worker Lorene Farrell. Caroline, guided by a private investigator, arrives to confront her rival and instead learns that Darla fled because she believes Preston is her brother. When Lorene mistakes Preston for the man she loved twenty-five years earlier, he reaches the same conclusion, and despair drives him onto a railroad trestle, where he narrowly survives an oncoming freight train.
 
Then Lorene confesses that Darla's birth mother was her friend Rae Ann Pruitt, who died in childbirth, and that Darla's father was Rae Ann's own father, Amos, who still lives across the road. As Caroline and Darla search for Preston with proof that he and Darla are unrelated, Eleanor arrives with a cashier's check and her husband's revolver, demanding that Lorene deny him. Preston, having just found a photograph of his Black birth father, interrupts the confrontation; Eleanor turns toward his voice, the gun fires, and he falls wounded. At the hospital, Charles still claims Preston as his son, Eleanor begins to accept responsibility, and Lorene tells her where her dead child is buried. Preston survives, but the old arrangements do not: he and Darla part, Caroline forgives him while leaving their marriage undecided, and Lorene gives him his birth father's last known address. Alone, Preston opens an old Christmas card from Detroit and begins to read.