Hye-ok (Jo Mi-ryeong), a middle class woman, lives happily with her husband, Jeong Hak-su (Lee Min), a doctor. She has no worries save that she has no children. One day, a boy named Sin-o (Ahn Seong-gi) visits her and alleges that he is a son of her husband. The boy's mother is Gye-sun (Lee Gyeong-hee) who spent one night with her husband seven years ago during the war. Gye-sun gave birth to the boy and has raised him in secret, but now that she is due to die of a serious illness, she has no choice but to send him to his father. Hye-ok feels betrayed by her husband. While her husband is away on a business trip, she decides to deal with the boy. She tries to send him off to an orphanage, but he strongly opposes it and she brings him with her. While Hye-ok lives with him, she feels maternal affection for him, and Sin-o becomes fond of her, too. Returning home from a business trip, her husband begs forgiveness from his wife, who is about to leave, saying that on his way to seek refuge it was unavoidable to spend a night with Gye-sun. Meanwhile, Sin-o, who goes to the railway track to wait for his mother, falls down on the track while following a train. Gye-sun, who has missed her son so much, saves him but is run over and killed instead. Going out to search for Sin-ho, Hye-ok and Hak-su find Sin-o crying by his mother's body. Hye-ok hugs him tightly.