Yoko, the wife, grew increasingly lonely due to her husband's single-minded focus on work and neglect of their home life. She ended up having a physical relationship with her brother-in-law, Katsumi, using it to fill the void in her heart. As they continued their weekly trysts, Yoko's feelings of guilt towards her husband gradually transformed into love for Katsumi... One day, Katsumi had to go abroad for work. Seeing his relationship with his sister-in-law as serious, Katsumi tried to decline the assignment, but Yoko insisted on him staying…
