One weekend, while leaving his father Toshio at home, Kenichi went out with his mother—but his mother suddenly remembered an appointment and returned earlier than expected. Upon arriving back, they caught Toshio with his young mistress, Tsubaki, inside their house. Shocked, the mother immediately left for her parents' home, and Kenichi confronted his father. Though Toshio promised to stop seeing Tsubaki, she refused to accept it and unexpectedly showed up at the house, taking her frustration out on Kenichi.