Not only does the aunt return to Boston in order to settle details of a bachelor estate of a relative, but she is drawn back from a buried, aching nostalgia for the music that she has left behind, the food on which her soul once fed. So starved for this music is Aunt Georgiana, that she cannot at first react as the long years without it have caused her to repress the yearnings and replace them with concerns about "old Maggie and her weakling calf."
When the first number is played, the Tannhauser, and the notes break into her memory, Aunt Georgiana clutches the sleeve of Clark:
...this broke the silence of thirty years, the inconceivable silence of the plains....It never really died, then--the soul that can suffer so excruciatingly and so interminably; it withers to the outward eye only,...she wept so throughout the development and elaboration of the melody....almost continuously.
Reunited with her old love, the music of Wagner,music in which "hope has lain down with hope and dream with dream...." Aunt Georgiana realizes what she has so long missed. Outside the concert hall, Aunt Georgiana confesses, "I don't want to go, Clark. I don't want to go!"
There are only two primary characters in "A Wagner Matinee" by Willa Cather; they are Clark and his Aunt Georgiana. Georgiana was once a teacher at the Boston Conservatory and was obviously a talented musician. She fell in love with a young, rather disappointing young man and left with him to settle a homestead on the prairies of Nebraska.
Clark lived with his aunt and uncle when he was growing up, and despite her very difficult life, she continued to love the classic and beautiful things in life, such as music and the arts. Clark eventually moved away to Boston, and when the story begins he receives a rather last-minute letter from his Uncle Howard saying that his Aunt Georgiana will be coming to visit--tomorrow.
The explanation is simple. Clark says:
It [the letter] informed me that his wife had been left a small legacy by a bachelor relative who had recently died, and that it had become necessary for her to come to Boston to attend to the settling of the estate.
We never hear anything more about this business throughout the rest of the story. Because we discover how connected she is to the land and her life back on the farm, she had to have a very good reason to leave, and this is as good as anything else Cather could have imagined for her. Obviously the author could have given us all kinds of details but chose not to; we can assume, then, that the reason she came to Boston was not important. Instead, what she experiences when Clark takes her to the symphony is the most significant thing in the story.
For more helpful insights on this story or on Willa Cather, see the excellent eNotes sites attached below.