Ryoko, a wife, is dissatisfied with her husband who often comes home late at night. Her son also spends his days working late-night part-time jobs, making for lonely days. One day, Ryoko indulges in her husband who comes home early for the first time in a while, and enjoys some marital sex for the first time in a long time. However, that day is also the day off for her son, and he can hear Ryoko's moans. Her son starts drinking in the kitchen to try to hide his frustration. When his mother comes in for a drink of water, she is pushed down by her drunk son, and they cross the forbidden line...