The story is...
Miranda, the young narrator of "Old Mortality"—the first novella in the Katherine Anne Porter collection Pale Horse, Pale Rider—accidentally encounters Cousin Eva, a relative, in a train compartment while on the way home to attend the funeral of her aunt's first husband, Gabriel.
The story is structured as a triptych, of which this episode, "1912," is the last. In the first, Miranda recounts romantic tales of her grandmother's about her beautiful Aunt Amy, who had toyed with the affections of so many suitors, before finally agreeing to marry the long-suffering but dashing and handsome Gabriel. Tragically, she died of tuberculosis a few weeks after their wedding.
In the second episode, "1904," the narrator, her father, and her sister run into the now middle-aged Gabriel at a racetrack, where he ekes out a meager living racing horses. The romantic legend of yore has turned into an overweight drunk, stuck in a miserable marriage and tortured by memories of the lovely Amy.
Cousin Eva, whose bitter version of these events dominates the final episode, is a blunt and intelligent old woman who has had a career as a teacher and a suffragette. A plain woman, she was ignored by the men at these romantic Southern balls where Amy was the focus of attention.
Although she claims to love Amy, Cousin Eva rejects the legend that has grown around her; she was no great beauty but simply a good-looking, giddy flirt. Like all the Southern belles at these events, she was put on display in a cold-blooded marriage market, carefully shielded from knowing anything about sex or the nature of married life. She believes that Amy might have committed suicide with the drugs she was given after her hemorrhage.
As disturbing as her perspective is, Miranda realizes Cousin Eva is as fixated on these distant events as was her grandmother. When her father passes by her at the train station to greet his contemporary, Cousin Eva, Miranda realizes that he, too, shares a past that is smothering her; "I can't live in that world any longer, she told herself..." She has a new awareness of a need to break away from this history, to make her own present.
At least I can know the truth about what happens to me...making a promise to herself in her hopefulness, her ignorance.