The narrator is first person and nameless. We don't know his or her gender and whether or not it is supposed to be the author, Willa Cather.
The narrator crossed Iowa on a train last summer and travelled with a childhood friend named Jim Burden. They both live in New York now but they don't see each other too often.
Jim is a lawyer married to a distinguished woman named Genevieve. He is passionate and loves his country. He works for one of the railroad companies.
During their time on the time together the two old friends talk about a Bohemian girl named Ántonia they knew when they were children. (Bohemia is a region of Czechoslovakia in Central Europe.)
To both the narrator and to Jim, this girl conjures up images of their childhood.
Jim wants to know why the narrator has never written anything about Ántonia. The narrator says she didn't know Ántonia as well as others did, such as Jim. Maybe they should both write down everything they know about her. Jim says maybe he will.
A few months later Jim shows up at the narrator's place with this manuscript. He calls it "Ántonia" at first but then changes it to "My Ántonia."