Sachiko is a wife who lives with her husband who runs a hot spring inn in the countryside. One day, her son, who lives alone in Tokyo, comes home and the family spends some time together for the first time in a long while. That night, the son accidentally witnesses the couple's nighttime activities and is filled with a sense of frustration. The next day, the son comes across his mother in the open-air bath while she is bathing, and unable to control his lust, he rapes her. Sachiko, despite verbal resistance, is aroused...