The narrator of The Setting Sun, Kazuko, grew up as a member of the Japanese aristocracy. Now, aged 29, she and her family have fallen on hard times. She recalls a time when Naoji, her younger brother, complained that the titles that once defined their family were not earned. Simply having a title was not enough to make a person an aristocrat, he believed. The siblings’ mother, he insisted, is the “genuine article.” She has the air of a real aristocrat, carrying herself with a grace and an elegance that denotes her class.

Kazuko’s breakfast is interrupted by a stifled cry from her mother. Her mother explains that she is upset by the thought of Naoji. Kazuko’s younger brother is a soldier in the Japanese Army. He was serving in the South Pacific during World War II, and now he is missing. Kazuko thinks about her pain, including illness, failed marriage, divorce, and her infant’s death. Only beautiful and sweet people die young, Kazuko tells her mother. Her “delinquent” brother is not such a person. He would obstinately refuse to die, she believes. The thought makes her speculate briefly about the future death of her mother, which she puts from her mind.