I'm Toshio, 54 years old. My wife, Chisato, is 49, and we have no children. We both remarried five years ago after being divorced. She has one son from her previous marriage, who's now an adult and married himself. So I'm like a distant relative to her son, and we only meet a few times a year. Although we remarried late in life, our sexual chemistry turned out surprisingly good—we've been intimate about once a week. However, I've always disliked kids, and worried about accidentally getting her pregnant, so I've consistently used condoms during sex. My wife is close with a friend she met through a women's association, and our families get along well. The couple is much younger, around the age of our children. Yet our relationship with them is unusually smooth, and I've actually looked forward to seeing them. Then one day, I witnessed something shocking about my wife...