At the end of the summer, when Murasaki no ue's condition is stable, Genji, who calls on her to inquire after her health, happens to find a love letter from Kashiwagi and finds out the truth.
紫の上の病状も小康状態になった夏の末頃、見舞いにやって来た源氏は偶然柏木からの恋文を見つけ、事の真相に気付く。