
She ends the letter addressing Uehara once again as M.C., this time resolving the initials as "My Comedian". She reveals that she is pregnant, and wants to raise the child on her own, disposing of the old morality and embracing a new revolutionary way of life. The story ends with a letter by Kazuko to Uehara. Shortly after, Naoji commits suicide, leaving behind a letter to his sister which gives his feelings of weakness over his aristocratic descent as the reason, also denouncing all ideologies which suppress the individual.

Kazuko eventually meets Uehara, years after their first encounter. Kazuko sees a black snake on the porch and remembers how her father died when one was present. Meanwhile, her mother's health is deteriorating, and she is diagnosed with tuberculosis. She repeatedly refers to ideas of Christianity and Marxism, having read a book by Rosa Luxemburg which she found in her brother's belongings, and dedicates the letters to "M.C.", resolving the initials both as "My Chekhov" and "My Child". She declares that she loves and adores him and wants to have his child, although she knows that he is an alcoholic. Kazuko writes to novelist Uehara, an old acquaintance and mentor of her brother, whom she once met when she was still married. Kazuko finds Naoji's "Moonflower Journal," in which he rants about people's bigotry and insincerity, and writes about his addiction and his struggles as a writer and individual. He treats his mother and sister cruelly, and spends most of the time among Tokyo's literary circles which he had been associated with before he was drafted. He is addicted to opium as he had been before the war. Kazuko and her mother move to the Izu peninsula countryside with the help of a relative, and she begins working in the fields to support them, claiming to be growing into a "coarse woman". It is revealed that at the time of Kazuko's father's death, there were many snakes present in and around the house, which therefore have become ominous in her and her mother's eyes.

Kazuko recalls a time when she burned snake eggs, thinking that they were viper eggs. Naoji, who served with the military in the South Pacific, is declared missing. The child she had been expecting was stillborn. Kazuko had been married, but divorced and returned to the family household after claiming that she had had an extramarital affair with a painter she admired. Twenty-nine year old Kazuko, her brother Naoji, and their widowed mother are members of an impoverished aristocratic family living in post-war Tokyo. The story centers on an aristocratic family in decline and crisis during the early years after World War II. The Setting Sun ( 斜陽, Shayō) is a Japanese novel by Osamu Dazai first published in 1947.
